Does Natural Algae Control Actually Work

At some stage in practically every aquariums life it will become the end result of an algae outbreak. Quite often these outbreaks simply disappear on their own, however on some occasions they simply will not go away and no matter what the aquarist does they simply return.

It is important to understand in the first instance why algae takes hold and grows in the aquarium.

All algae require an energy source. This energy source could be a particular colour temperature in the light, a nutrient in the water etc.

Therefore the algae outbreak could be due to the lighting not being replaced and the incorrect colour spectrum being transmitted into the aquarium. Some algae like this particular temperature and then grow. The light to the human eye will probably look fine however unless you perform a specialist test you will not know. The best thing to do is ensure that you change the bulbs at the correct time period based upon manufacturer’s recommendations.

The second and probably the most common one is where algae feed upon nutrients in the water. The most common nutrients and nitrate, phosphate and silicates. In this scenario especially for nitrate and phosphate it can be hard to locate. The reason for this is that the algae are taking up the nutrients from the water column and therefore when a test is performed the parameters appear to be ok. As soon as the algae is removed from the aquarium the levels start to increase and the algae takes hold again.

It is a vicious circle unfortunately.

As the saying goes though - prevention is better than cure.

The best prevention is to ensure that the equipment in the aquarium is correctly maintained and replaced if/when required as well as the water parameters being kept at the highest possible standard.

A very useful part of obtaining these parameters is the reduction/removal of nutrients. An excellent way to reduce and/or remove nitrate and phosphates is through the use of natural based control.

This natural based control could be live rock, deep sand beds, mud beds, refugiums, mangroves etc.

Live rock for example is exceptionally powerful at filtering the aquarium and if enough high grade quality is purchased then it can also assist in the reduction/process of nitrates.

It is my opinion that there are two natural based packages which can be used for both filtration and nutrient export.

These are:

1. Live rock combined with a deep sand bed - This allows for efficient filtration of the aquarium via the live rock and also for nutrient export via the deep sand bed.
2. Live rock combined with a refugium - This again allows for the efficient filtration of the aquarium via the live rock and also for nutrient export via the refugium where macro algae is grown.

In the refugium example above I personally find it interesting that you can use algae to control algae. The reason this can be performed is that the algae which you are growing in a separate aquarium can be harvested from time to time. The algae removes nutrients from the water and uses this for growth. When the algae is harvested from the aquarium the nutrients are removed as well. As you are not removing all of the algae then the remaining algae feeds upon the nutrients in the water and maintains these parameters at a low level. Because the algae is located in a separate aquarium no or minimal algae outbreaks should occur in the main display aquarium. This is not to say you will never receive any because you might however it severely reduces the possibility.

These are not the only methods which you can use as there are many more. Mangroves for example are very powerful but they are very slow growing and therefore reduce the nutrients at a slower speed.

The aquarist, however should never rely upon these techniques and needs to ensure that the correct care and maintenance is still employed, the fish are not overfed etc.

Simply put in response to the question in the title of this post - yes natural algae filtration does work as long as it is properly implemented and cared for.

Follow nature and keep it simple.

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Tags: Algae, Aquarium Filtration, Aquarium Maintenance, Care, Equipment, Problems

You Need To Have Enough Filtration In Your Aquarium

A successful marine aquarium is a wonderful sight. It doesn’t matter whether it is a fish only, coral only, or fish and coral system, there are certain items that need to be up to the job.

The first essential requirement is seawater quality, closely followed - at least in a coral only or coral and fish aquarium - by lighting. It is the need for seawater quality that makes filtration so important.

There are basically two types of aquarium filtration, excluding protein skimming which is often counted as such. The first is mechanical/chemical filtration and the second biological.

Mechanical filtration is where media removes sediment from the seawater by trapping it in suitable media. This is often done by using a canister filter which needs to be cleaned regularly and the media changed if it is showing signs of wear or failure. Mechanical filtration is not an absolute requirement and many aquarists do not use it. It is usually only necessary when there is a fair amount of sediment floating around in the seawater. Before employing a mechanical filter, it is best for the aquarist to ascertain why there is sediment and try to correct the problem.

Chemical filtration is also often done by using a canister filter and can be in conjunction with a mechanical stage - if so the mechanical stage normally comes first. Chemical filtration covers activated carbon, phosphate removing media etc. Again it is not mandatory to use this type of filtration, though some aquarists use activated carbon to supplement the protein skimmer and others run an anti-phosphate media continuously (phosphate is a nuisance algae nutrient and is mainly introduced with food).

By far the most important filtration is biological, and this applies to any type of system. The filtration carries out the ‘Nitrogen Cycle’, which is something all aquarists should clearly understand. Livestock introduce a toxin into the seawater, namely ammonia. This toxin is deadly to life forms in low concentrations but fortunately Nature has the solution. The biological media provides a home for bacteria in their millions, and the first group of bacteria convert the toxic ammonia into nitrite. Unfortunately nitrite is also a toxin and very nearly as bad as ammonia. However, a second group of bacteria convert the nitrite into nitrate, which, though problematical in a high enough concentration, is not generally harmful. If the Nitrogen Cycle is able to run the full course the nitrate is converted to gas which escapes the seawater.

There are one or two points that need to be remembered about the bacteria that provide this essential service. The first is that the bacteria that convert ammonia and nitrite are oxygen hungry, and to ensure their proper function it is necessary to provide seawater rich in oxygen by having adequate seawater circulation and air/water interfaces.

The bacteria that are able to convert nitrate to gas are not the same. They would use oxygen if it was available, but if it is not they take the required oxygen from the nitrate, thus breaking it down. Therefore the bacteria need to be in a very low or no oxygen environment to ensure that the required function is performed.

If for example a canister filter is being used for biological filtration the media is constantly exposed to oxygen. Therefore the breakdown of ammonia and nitrite will occur but nitrate conversion will not. Nitrate will remain in the seawater and will increase unless other adequate measures are taken.

If the biological filtration is by good quality live rock, then the full Nitrogen Cycle, that is ammonia-nitrite-nitrate-gas, should occur. This is because the oxygen loving bacteria accumulate near to the surfaces of the rock, and the bacterial nitrate converters are deep inside where oxygen is depleted.

Having considered all of this, it is clear that there needs to be adequate filtration material to accomplish the biological task. For example, a fish only system can employ live rock. Fish are producers of ammonia, much more so than corals, and an adequate amount of good quality live rock is needed to process the toxins. The live rock amount would need to be increased if the fish numbers were high as obviously there would be more toxins produced. As a general guideline 1½lbs of good live rock is considered necessary for each gallon in the complete system. So if there is a sump, count that in. There is a problem with the ‘weight system’ as live rock can be of differing weights, therefore when purchasing seek advice.

Similarly, when using a canister filter (or similar) for bio-filtration it is important to ensure two things - first that the canister can contain sufficient bio-media for the intended load and second that the flow rate through the filter is adequate. Manufacturers will advise the recommended aquarium size for canister filters, and media manufacturers will advise the suggested bio-loads.

Mechanical/chemical filtration is not so essential, so reading the media manufacturer’s recommendations is sufficient, if these types of filtration are required at all.

Stocking a marine aquarium without an adequate amount of bio-filtration will soon become obvious to the aquarist - sickly livestock and quite likely losses. Inadequate bio-filtration is likely to hit fish systems the most as they produce most toxin with their life functions. However, all systems require adequate bio-filtration, Nature’s free and essential service.

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Tags: Aquarium Filter, Aquarium Filtration, Aquarium Lighting, Care, Equipment, Water Quality

Why Is Water Movement So Important In A Home Aquarium

Let’s take a quick look at the ocean - it is a vast area which is exceptionally dynamic. The animals which live in the ocean, some of which make it to our aquariums are used to the action of the water movement.

The secret of a successful marine aquarium other than research and patience is optimum water quality, adequate lighting and water movement.

Water movement is not something which is appreciated by marine aquarists but is normally something which is provided as it is believed that it needs to be provided. To appreciate the important of water movement it is important to understand its role in nature, understand the requirements of the animals and then finally work out the best way to provide the required water movement.

Water movement’s role in nature is for many things. It allows for gas exchange, the provision of dissolved oxygen, the provision of food to animals, the removal of waste, the exchange of nutrients between filtration methods (In the wild this could be between the reef itself and grass beds/mangroves etc).

Water movement within the home aquarium has a simple term which is simply ‘turnover’ which is also classified as the amount of water which is moved around the aquarium per hour. There is a standard minimum turnover for a reef aquarium which is 10 times per hour. Therefore if you have an aquarium which is 100 gallons then you will need to ‘turnover’ the aquarium water 1000gph.

It is not as simple as purchasing the correct amount of water pumps, powerheads, wavemakers to facilitate the correct amount of turnover. There will be some fine tuning required in order to provide the correct types of currents to the animals in the aquarium. This is especially true when corals are being kept as their water movement requirements are higher than that of fish. Corals unlike fish do not have the ability to be able to walk around the aquarium in search of the ultimate spot. Some anemones do have this ability and move around the aquarium looking for the perfect location. Unfortunately quite often this is round the rear of the tank out of sight!

I shall have to get a little bit scientific here in order to explain why corals require strong water currents. Hopefully it will not get confusing. When water flows around a coral its viscosity increases due to friction. At the water/coral interface the water is at its highest viscosity - basically the water becomes really thick and due to this a stagnant area of water is evident around the coral. When this happens the coral literally poisons itself due to the inability for diffusion to occur. Obviously this is not something that we want to happen and the correct amount and type of water movement needs to be implemented. We cannot just point an outlet from a powerhead directly at a coral as this will not be appreciated and could again kill the coral.

Whilst fish do not have the same requirement for strong water movement as corals do there are a lot of fish who respond better when kept in an aquarium with strong water currents. Feeding time is more natural and the fish continuously move themselves around to be in the correct flow pattern where both essential oxygen and food is provided.

Another area to consider is the filtration itself. If live rock is used then enough water movement needs to be provided to allow the water to be able to move over, around and into the rockwork so that the bacteria can do its job. If not enough water movement is provided there will be areas in the aquarium where the water is not moving and stagnant. These areas effectively become bad and are not being processed by the filtration. Live rock can only process the water which passes over it therefore if the water is not moved to the filtration area then quite simply it will not get processed and before long the water quality will begin to suffer. From here the slippery slope begins.

One area which is often forgotten about is the air interface - the surface of the water. If flow water movement is provided then the low oxygen areas in the water will stay near the bottom of the aquarium and the oxygen rich areas near the top will stay near the top. For the air/water exchange to work effectively the surface of the water needs to be broken. This can be achieved in many ways - it can be achieved using a spray bar, a small powerhead pointing up to the surface of the water or can with enough water movement in the aquarium be created all on it’s own.

What we need to achieve is a lot of water movement in the aquarium using what is called a wide flow. The output from a powerhead is a thin flow and whilst powerful is damaging. The flow itself does not want to be laminar in pattern i.e. all in one direction instead it needs to be chaotic/turbulent.

Looking at the corals in the wild we can see that they sway in all directions as the water currents move them around. If you have ever been scuba diving or even snorkelling on/over a reef then you will appreciate how water movement in nature works.

Another type of flow which is very popular is what is called surge flow where the water flow in a back and forward type of action. There are various devices available which assist in the creation of this type of flow and also various do it yourself plans available however personally I believe that even this type of flow needs to be broken up so that is becomes turbulent.

I am a firm believer in trying to emulate nature as much as possible in the home aquarium and water movement is no exception. Quite often in the wild the water currents reduce due to the lack of wind at the waters surface. Again this is relatively easy to achieve with a light sensor which either reduces the speed of the pump or turns it off altogether.

The aquascaping in the aquarium will also have an impact on the flow in the aquarium. When the water flow hits or passes over the rocks then friction will occur and this will effectively reduce the amount of flow in the aquarium. The same can be said for corals especially hard corals as they grow larger. As they grow the flow in the aquarium will change and will need to be periodically reviewed. Due to the rocks and corals in the aquarium there will be areas of the aquarium where the water flow is significantly different. This is not too much of a problem as long as corals are placed in locations which are suitable for their requirements - both water movement and lighting. It is imperative however to ensure that there are no areas of stagnant water as this will create problems further down the road.

When planning the water movement in the aquarium there are normally two factors which are taken into consideration. The first one is the requirements of the animals in the aquarium and the second one is cost.

Powerheads are normally the aquarists first choice as they are cheap to purchase and can create good flow within the aquarium with careful positioning. As already stated we need to be careful to ensure that the flow is not pointed directly at a coral as damage can occur.

Wider pumps are available which have a much wider outlet and instead of an impellor have a propeller type device and this creates a strong yet soft flow if that makes sense which therefore means that flow can be provided which is much more beneficial to the corals in the aquarium. Care still needs to be taken with placement so that no damage is caused to the corals however the flow created is much more natural.

There are various other methods which can be utilised. Wavemaker devices can be implemented to create random flow. These can be automated devices which switch pumps on and off to create a random flow. Again care does need to be taken with these are powerheads/pumps are not created to be turned on and off all the time and damage can occur to the powerheads/pumps. Other wavemaker devices are also obtainable which are similar in design to those of wavemaker devices in swimming pools.

Another option which is my personal favourite is the implementation of what is called closed loop. This is where the pumps are located outside of the aquarium and flow is directed into the relevant areas of the aquarium using pipework.

It is my opinion that water movement is one of the six important factors of a successful home aquarium.

These are:

Planning, patience, research, water quality, lighting and water movement.

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Tags: Aquarium Filtration, Aquarium Lighting, Aquarium Maintenance, Care, Equipment, Water Movement

Can Decorative Sand Be Used For Filtration

This is a very good question which I was asked recently via email and I thought that I would detail it here for others to read and hopefully benefit from.

A lot of aquarists decide to put a small amount of decorative sand in the bottom of the aquarium to make it look more natural. This sand is normally something like coral sand, live sand etc.

Normally a small scattering is put in the aquarium - just enough to cover the bottom of the aquarium. At first the aquarium does look very natural however before long the sand starts to get clogged up with detritus, uneaten food and unless the aquarist cleans it then it can start to look very dirty.

Whilst looking into possible methods to keep it clean the aquarist may stumble upon a term called deep sand beds. After a small amount of research the aquarist may decide to ‘give it a go’ and after purchasing more of the sand installs it into the aquarium and believes that he/she now has a deep sand bed.

Wrong I am afraid and this is a deep sand bed which is probably destined to fail.

The reason for this is that the sand used in a deep sand bed has to have sand particles which are within a given size range. This is so that the animals which live in the sand are able to move the sand around. This is a term which is called turning the sand bed over. The animals will not magically appear. Some will migrate from the live rock if this is used in the aquarium, however the majority will need to be introduced by the aquarist. Not just once either the bed will need to be topped up from time to time. Once the bed has animals in there they then need feeding so that they can reproduce and increase the diversity in the sand bed. For this they need to be fed by placing some food directly onto the sand bed alternating where the food is placed. Other animals can also be purchased and introduced to the aquarium to assist in the cleaning up of the sand bed. These can be hermits, starfish etc but they have to be ones which will survive in a sand bed.

The other thing that is required is the actual depth of the sand bed. The sand bed needs to be a minimum of four inches in depth. Having a deep sand bed of at least this depth will create a bed which is low in oxygen at the bottom. When this happens this allows for the relevant bacteria to live which will assist in the filtration.

There are a large amount of aquarium stores now that sell sand which is designed for use in the the creation of a deep sand bed. There is a variety of colours to choose from however personally I prefer the natural ’sand’ looking colour!

A deep sand bed is a very powerful tool for filtration and is often underestimated. Combine a deep sand bed with live rock and you have an aquarium filtration system with a large amount of power. As long as it is properly setup and properly cared for.

In answer to the question - yes decorative sand can be used for filtration as long as the fundamentals of deep sand beds are understood.

Below are links to two articles we recently wrote on this subject:

The Deep Sand Bed - One Of The Most Effective Filtration Methods

Deep Sand Bed Construction

Feeding a Deep Sand Bed

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Tags: Aquarium Filter, Aquarium Filtration, deep-sand-bed, live-rock, plenum, Water Quality

The Aquarium Sump Can Be Used For So Many Things

Marine systems of whatever type, reef aquarium or fish only aquarium, can function successfully on their own without a sump, provided they are properly supported by equipment, are not overstocked and ongoing routine maintenance is completed. There is a way to enhance the seawater quality in the aquarium even if all the necessary guidelines have been followed religiously and that is to have a sump.

An aquarium sump is to all intents and purposes another aquarium attached to the main display. Seawater is pumped up from the sump to the display aquarium and flows down again by gravity, usually by the use of an overflow pipe. This flow is easily achieved.

All that is needed is to measure the available space for the sump - it could be inside the cabinet cupboard if there is one, in a separate housing alongside but below the main aquarium, or even in an adjoining room. Generally the bigger it is the better. Once the available space has been measured the aquarist can purchase a suitable aquarium. There will need to be at least two dividers in the sump, the first one is to accept incoming seawater and the last one is to create an area for the return pump. Some aquarists have more dividers for their own reasons, but two serve the basic purpose. The glass for these dividers does not need to be thick as there is supporting seawater on both sides. There isn’t any chance of a leak once they are siliconed in place as all joints are inside an already watertight unit. The finished job does not need to be perfect as it is in the sump and not on display. Measuring and siliconing the glass is a simple job, there needs to be an overflow at the top of each divider which is created by making the top of the dividers around ½ inch lower than the seawater level. If the aquarist doesn’t fancy the job then a local marine pet store will often do the job for not much money, especially if the needed aquarium has been purchased from the same shop.

The question of drilling the display aquarium for an overflow to feed the sump is one that puts many DIYers off. Again, the local marine shop will often do the job, or if not a local plumber often will. Alternatively, an overflow device can be used. These fit on the edge of the aquarium and seawater overflows by siphon. These units are available commercially, but do project above the top of the main aquarium to an extent so space needs to be available.

The first advantage in having a sump is that the system seawater gallonage has been increased. This means that seawater quality will be enhanced as there are more gallons per fish. Note that the extra gallonage created is not a reason to increase fish stocks as this would negate the advantage and also possibly create space problems in the main aquarium. There will also be an increase in the amount of seawater used for the routine seawater change; this is not a problem as generally the sump isn’t that large.

So what else could the sump be useful for? Again with a view to high quality seawater a deep sand bed (DSB) could be placed between the two dividers. The depth of the DSB usually starts at 4″ and many aquarists have them deeper than this. Note that ordinary coarse coral sand is not used as it needs to be fine sand. There is an article on DSB construction on the Aquarists Online website. Another way to achieve the same thing would be to install a plenum, which is a raised DSB. I believe most aquarists use a standard DSB. The aquarist should see many tiny life forms inhabiting the DSB which generally widens interest in the aquarium system.

The macro algae Caulerpa could be used in the sump. Again this algae is used for filtration as it feeds on nitrate and phosphate. Once established it needs to be harvested from time to time. The aquarist will need to provide lighting. This is not expensive to purchase or run as fluorescent tubes (T5’s or T8’s) fitted with reflectors are sufficient, usually two are positioned along the length of the sump. An electric timer is also needed if the aquarist is to run the lighting on a cycle. If so, it is advantageous to have the sump lights on when the main aquarium lights are off. The reason for this is that it helps stabilize pH.

Additional live rock could be placed in the sump (but not on top of a DSB as it would cause compaction). This increases the bio-filtration should this be needed and at the same time creates a new mini-world for the aquarist.

If the aquarist has a problem with a fish then, if the fish is not too large, it could go into the sump. This is not for treatment (if treatment cannot be done in the display aquarium then it cannot be done in the sump as the two are connected), but to give the fish some respite if it is being harassed excessively. Likewise, there is a place for any unwelcome hitchhiker that has arrived with live rock - for example, a mantis shrimp is not welcome in the main display aquarium but it could be transferred to the sump and become a point of interest.

Another practical advantage to the sump is that it can be the home for technical equipment that would otherwise be in the display aquarium. Heaters and a protein skimmer for example - the equipment is out of the display aquarium which benefits by the removal of unnatural items.

If the aquarist has room for a sump then it is very worthwhile adding one.

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Tags: Aquarium Filtration, Aquarium Maintenance, aquarium sump, Care, Equipment, marine-aquarium

Mud Bed Aquarium Filtration

Mud bed filtration is similar to that of other sand based aquarium filtration systems, however the substrate is made of such a small grain size that it is very much like mud. A good filtration method to equate a mud bed to is the refugium.

In the refugium filtration method various types of macro algae are grown in the fine sand. The mud bed filtration system is effectively the same, however instead of sand mud is used instead. It is not just normal mud though, it is a mud which is full of various elements and minerals. These elements and minerals are slowly released from the mud into the water column.

A mud bed system is normally run in an aquarium or some other container located under the main display aquarium. Some aspect of mechanical filtration is required to remove any large particles from entering into the mud filtration area. This can be performed at the end of the overflow(s) by passing the water through very small chunks of live rock etc. After the water has been through the mechanical filtration it enters the mud filtration aquarium. The macro algae consume nutrients from the water and various elements are slowly released into the water from the mud bed. The water then normally passes through some type of grid or through another chamber full of small pieces of live rock the purpose of which is to prevent any of the macro algae from leaving the mud area and blocking the return pump. Once the water has passed into the pump area it is returned to the display aquarium.

In a mud based system the lights are normally left on for 24 hours a day. This allows the macro algae to photosynthesise and grow. It is only when macro algae grow that they consume nutrients from the water. It is best to use lighting which is designed for the growth of plant life. A couple of fluorescent tubes will suffice, ensure as said that they are for plant life and have a Kelvin rating of around 6000. Lights with this Kelvin rating have more colour in the yellow/red area which benefits the plants.

A normal rule of thumb for a mud based filtration system is to pass in the region of 10 times the total water volume per hour. This needs to be considered when designing the aquarium system as the total amount of water in the system will determine both the overflow size and the size of return pump required.

As with a refugium there may be a requirement to harvest the macro algae if it becomes too dense. Never pull the algae out by the roots - instead cut the plants back with an old pair of scissors or similar. Harvesting the algae will allow more light to penetrate into the areas where the algae grows. One point to remember is that you should not add this macro algae back into the aquarium as you may reintroduce the nutrients back into the water.

A mud based system combined with macro algae removes a lot of the nutrients (nitrate, phosphate etc) and dissolved organic compounds as well as replenishing trace elements.

A lot of aquarists who utilise a mud based system for filtration do not run a protein skimmer. It is not recommended to do so by these aquarists because of the amount of particulate matter which is extracted from the water by protein skimmers. When viewing a mud based system you can actually see the fine particulate matter in the water. The water is still clear, however it is full of fine matter which some life in the aquarium can use for energy.

Of course there are also aquarists who do choose to run a skimmer, however the majority of these run the skimmer part-time (i.e. throughout the night, turned on/off via the use of a timer). The majority of these aquarists decide to run a skimmer as they are very wary of turning it off. I have run a system using a mud based method combined with live rock for many years without problems. The only thing you need to ensure when you run a system like this is that detritus is removed from the main display aquarium regularly and that weekly water changes are performed. A lot of aquarists who do not run a skimmer on their mud based systems do not have a sand bed in the display aquarium due to the build up of detritus which can occur. Instead they go ‘bare bottom’ in the aquarium. The glass which is visible at the bottom of the aquarium quickly becomes covered in coralline algae as well as other types of life so looks more natural as time passes.

The aquarists who decide not to run a skimmer have reported a higher level of particulate matter visible in the aquarium water which the corals, and other filter feeders consume. Because of the amount of particulate matter in the water column you should see good polyp extension from your corals as well as hopefully having success in keeping some of the harder to keep corals. Obviously you cannot just expect to be able to keep these more difficult corals just because you are running a mud based system - you must still ensure that you have optimal water parameters and that the requirements for the livestock in question are met.

Implementing a mud based filtration system is fairly straightforward. It is best to have an aquarium which is split into three or four sections. This can be accomplished yourself using glass and baffles or you can have one made for you at your local fish shop.

The first area is where the live rock is placed and is where the water from the display aquarium, via the overflow(s), enters the filtration aquarium. The purpose of this section is to remove any large detritus from the water as well as break up any air bubbles. Using live rock in this area is a good idea rather than another type of media as it is a natural filtration medium and will actively help in filtering the water rather than hindering it as other types of media could do.

The second section is where the mud is placed as well as the macro algae (caulerpa etc). The mud is poured into this section and the macro algae planted within it. To give the macro algae a chance to put its roots down trap it gently under a piece of live rock. Once the macro algae takes hold the piece of live rock can be removed. It is advisable to add a few varieties of macro algae as some may not take root. Caulerpa is one species which does tend to do well and there are numerous varieties available. Because of the amount of water flow which can be created in the central chamber some people choose to create small containers 1 inch or so high and 1-2 inches apart in the bottom of the chamber. This prevents the mud from moving around and building up in a pile at one end of the chamber.

The third or fourth section is where the return pump is located and is protected from the second central section via a baffle of some type or even more chunks of live rock contained in a chamber. If you are running this mud aquarium as your sump then your heaters for example can also go in this area.

A couple of fluorescent tubes will suffice for the lighting above the mud section and should remain on for 24 hours per day. As said attempt to use tubes which are designed for plant life as this will help the macro algae grow.

Because of the mud releasing essential elements into the water the mud bed will eventually expire, therefore it is recommended that half of the mud bed is replaced about every two years however I would recommend that you rely upon the manufacturers recommendations in this area.

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Tags: Aquarium Filtration, Care, deep-sand-bed, Equipment, plenum, Water Quality

The Plenum - Could It Work For You

The word plenum is not a term which the majority of beginners have actually heard of especially when it comes to filtering the aquarium. The plenum however is very similar to that of a deep sand bed however both the creation and design are entirely different.

So what actually is a plenum?

A plenum is not a filtration unit but is actually a space which is located under the substrate and separates the substrate from the bottom of the aquarium.

This space (the plenum) is full of both the water and any organic waste as the water is diffused into it. A plenum is also sometimes referred to as a Jaubert system as Dr Jean Jaubert was the individual who discovered it.

The structure of a plenum is actually very very simple. It is basically a deep layer of substrate which is suspended above the bottom of the aquarium to create a space or a void if you will.

How it works is, although slightly scientific, also relatively simple.

As the water moves slowly through the substrate the nitrifying bacteria in the upper level use up all of the oxygen in the water and convert the ammonia to nitrite and then the nitrite to nitrate. The nitrate which remains is the transported with the water down towards the plenum. As the water reaches the lower levels of the substrate the nitrate is then slowly broken down into nitrogen gas by the denitrifying bacteria which live in the very low oxygen levels of the substrate.

The reason the water moves slowly through the sand is due to the anaerobic action being performed in the lower levels. The anaerobic actions produces heat which heats up the water in the plenum area. This heated water moves up through the substrate which therefore displaces the cooler water above it causing the water to move through the substrate at a very slow rate.

A slow rate of water movement is important in a plenum as it assists in the prevention of a dangerous build up of hydrogen sulphide.

The upper levels in the substrate will become home to various organisms which can either be introduced via the aquarist or are organisms which have relocated from their home in the live rock. These are very important, the same as they are in a deep sand bed. Their job is to keep the upper levels of substrate ‘turned over’ and clean from both detritus and waste.

The above is how a plenum operates but how do you actually make one.

Again this is relatively simple. Not as simple as a deep sand bed as it does require a bit of DIY but simple all the same.

The items listed below are required to make the plenum. This list is not set in stone and can be modified to suit your/the aquariums needs.

Marine safe PVC piping.
Egg crate to make the grid from.
Screening.
Aragonite based sand with a granular size between 1 and 2 mm.
Live Sand.
Silicone.
Tie Wraps.

The recommended minimum required depth of substrate in a plenum is 2 ½ inches when placed on top of the plenum grid therefore you need to ensure that you obtain enough aragonite/live sand to accomplish this.

The first thing you will need to do is actually create the support which the substrate which sit on top of and create the plenum. Personally I find that marine safe PVC pipe is the best for this. These, when laid on their side provide a lot of strength for the substrate held above it.

I would recommend that you cut this piping in lengths of two inches or so and ensure that you have enough of them to support the weight of the substrate above it. Remember that you may also be placing rock on top of the substrate in the aquarium so make enough of them to support this as well. If you are unsure make more than you think you will need.

Once all the support have been kit you will now need to make the grid. The grid is basically there to hold the substrate up and also to prevent any of the substrate from falling down into the plenum area and effectively making it useless.

The easiest way I have found to do this is use eggcrate and cut this to the same dimensions as the inner dimensions of your aquarium. It does need to be noted that the grid needs to be a very tight fit so take your time cutting it. Once cut it can then be attached to the supports. I have found that tie wraps are excellent for this.

The basic structure of the plenum is not in place, however if the substrate was to be placed into the aquarium at this point it would simply fall through the eggcrate into the void. This is where the screen is used.

Cut the screen so that it is slightly larger than the inner dimensions of your aquarium. Once cut carefully place it into the aquarium, fold up the edges and carefully silicone it to the side of the aquarium. You will need to allow the silicone to cure which normally takes about 24 hours but once cured you should have a screen which no substrate will fall through.

Once cured you will be in a position to add the lower level of substrate. Add 1 ½ inches or so of aragonite and give it a really good stir using your finger to remove as many pockets of air as possible. Also be exceptionally careful not to tear the screen otherwise all your hard work will go to waste.

Now that the first layer is in place you will need to cut a second screen to slightly larger than the inner dimension of the tank, and silicone it in place as you did the first screen.

Once the curing process is complete put another 1 ½ inches of the aragonite sand into the aquarium. As with the first layer give it a really good stir with your fingers to remove as many air pockets as possible again being careful not to damage the screen.

Now we are ready for the live sand. Add about 1 inch or so of live sand to the top of the final layer - a screen is not required this time as it does not matter if the live sand mixes with the top layer.

The plenum is now complete and ready for water. When filling with water fill it slowly to avoid creating any air bubbles and mixing all the sand up.

So now we should have a plenum area at the bottom topped with a screen, on top of this screen is some aragonite sand followed by another screen. On top of this screen is some more aragonite sand and then the live sand. All of this is supported via some pvc piping to take the weight and create the plenum space.

In a plenum system it is recommended that little or no water flow be directed across the surface of the substrate. It is also recommended that a protein skimmer be utilised with a plenum as this will assist in the removal of any dissolved organic compounds which are not removed by the plenum.

It is easier to introduce a plenum to a new aquarium rather than the modification of an existing one. If you are interested in introducing a plenum to an existing system you will either have to remove everything from the display aquarium to introduce it or build a plenum in a separate aquarium and attach it to the system using overflows and pumps.

As with the introduction of any filtration device you will need to monitor the water parameters carefully so that you know that the nitrogen cycle is functioning properly.

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Tags: Aquarium Filter, Aquarium Filtration, Care, Equipment, marine-aquarium, saltwater-aquarium

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