Can Tonga Live Rock Provide Enough Filtration?
May 11, 2008
Live rock as has been said time and time again is a phenomenal filtration medium. There are various different types of live rock available all of which provide the required filtration to the aquarium if enough is placed into the aquarium.
There is one in particular however that in my opinion is more decorative and ’standard’ live rock.
Tonga rock
Tonga rock is different to other types of live rock due to the reason that it looks like branches of a tree. It can be an extremely decorative addition to a saltwater aquarium. Due to tonga rock being thinner and not boulder shaped like the majority of other live rock with the obvious exception of plating rock you have the ability to be able to create fantastic water movement around it.
In my opinion tonga rock is fantastic for SPS corals as you can provide a large amount of water movement and if carefully aquascaped can look amazing. This is not to say that you could not have a fish only aquarium or a soft coral aquarium with tonga rock as you would be able to. You would just have to bear in mind that you will need to create caves etc for the fish to hide in as well as creating ledges to place the soft corals on.
But what about the filtration - is tonga rock as good as other live rock.
Tonga rock does have good filtration capabilities however they are not as good as other live rock. This is mainly due to the size of the physical rock. To purchase enough tonga rock to faciliate the filtration requirement would make it very hard to aquascape.
So what do you do?
In my opinion it is quite simple. I personally would use the tonga rock for decorative purposes and then have an in tank deep sand bed as well. The deep sand bed would be the main aspect of the filtration but the tonga rock would do some as well albeit reduced. You do not need to have the deep sand bed in the display aquarium it could be in the sump in the cabinet. You would just need to make sure that the partiton designed for the deep sand bed was large enough.
One of my dream aquariums (we all have them don’t we) is to have a 3 foot cube tank (3*3*3). In this aquarium a deep sand bed would be placed and tonga rock used for decorative purposes as well as some plating rock to provide some hiding places/ledges. Lighting would be provided by metal halides, the water movement would be chaotic and my corals of choice would be SPS with a small amount of fish.
We can but dream can’t we?
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Tags: Aquarium Filter, Aquarium Filtration, Care, deep-sand-bed, live-rock, refugiumCan You Add A Deep Sand Bed To An Existing Setup?
April 23, 2008
Every week I like to pop into my local fish shop, even if it is not to purchase something just to have a look about and have a chat with the owner.
Over the years we have built up a bit of a friendship and over a cup of coffee we tend to sort the world out – both aquatic and non aquatic related!
Anyway whilst I am in there other people of course come in and ask various questions, purchase things and I like to keep out of the way whilst this is happening. I normally go and look at the corals and fish with my cup of coffee in hand.
Yesterday whilst I was there I overheard a conversation between a customer and the owner of the store entailing deep sand beds.
It is probably obvious by now that I am a huge fan of deep sand beds.
Basically the customer had heard that you cannot add a deep sand bed to an aquarium system which is already setup and the owner of the store was patiently attempting to explain to him that it was possible to do so.
The conversation did not get heated but to cut a long story short the customer would not take any advice from the store owner (the expert if you will) and left the store. As far as he was concerned this is what he had been told so it must be right!
It must be very hard for owners of shops, not just fish shops but any shop for that matter to deal with situations like these.
We chatted about it afterwards and he said that although it is hard he will not tell anyone incorrect information even if it means losing their business. It is not just about the money he earns but the love for aquatic life which he sells.
To be honest what he was discussing with the customer was correct and I thought that I would cover it here in case any readers of Aquarists Online have been wondering about this as well.
If you are interested in understanding more about deep sand beds then click the link below :
The above article covers how a deep sand bed works, the importance of grain size etc etc.
What we will cover in the remainder of this article is the introduction of a deep sand bed into an existing aquarium system.
It is presumed that you have purchased sand which is of the correct particle size.
I would advise that any sand purchased is cleaned thoroughly in saltwater. The saltwater removed from the aquarium when you do a water change would be fine for this use. An even better way than just washing the sand is to leave the sand covered in saltwater for a period of a couple of weeks.
Some aquarists even run a magnet over the surface of the sand just in case there are any metals in there but this is not a definite requirement.
Once the sand has been prepared you are now in a position to be able to add it to your aquarium.
If you have any sand in your aquarium and it is not of the correct granular size then it will need to be removed from the aquarium. Do not discard it though as you can use some of it to ‘seed’ the new sand bed.
If you have any sand in your aquarium and it is the correct size then it can be left in the aquarium, however do not be tempted to add all of your new sand in one go – add it slowly over time. The reason for this is that when you add new sand the life which lives in the existing sand needs to move higher up in the sand bed and if you put to much in at one go then you may kill them.
Due to displacement some water will also need to be removed from the aquarium.
Turn the pumps/powerheads off in the aquarium and slowly add the sand to the bottom of the aquarium.
Do not be tempted to lift any of your rocks off the base of the aquarium simply add the sand around the rocks.
If you did lift the rocks off the base of the aquarium and then place them back on top of the sand then this would cause compaction in the sand and the bed will not function.
With you adding the sand around the base of the rocks compaction can occur and more importantly the little beasties can migrate from the rock into the sand. It is important to have a huge diversity of life within the sand bed as they consume the detritus in the bed as well as ‘turning over’ the sand.
The pumps/powerhead can now all be turned back on again.
With you having a running aquarium system then you will no doubt get a sand storm in the aquarium. This will clear quite quickly.
Once the bed is in place if you removed and old sand from the aquarium then some of this can be placed on top of the new sand bed as this will help introduce the valuable little creatures into the bed.
Your job now is to feed the bed to ensure that the population grows and grows. Regular feeding will be required and can be achieved by simply placing a cube of frozen food daily on top of the sand bed. The food can be held in place by a stone, shell of something similar. Vary where you feed the bed and over time the population will increase and before long you will an exceptionally powerful filtration device – especially if you combine it with live rock.
I suppose that there is also a moral to this article as well as some information being provided in relation to the introduction of a deep sand bed.
The moral is that you are not always right. Listen to what other people have to say, take their advice and then make your own decision.
Tags: aquarium, Aquarium Filter, Aquarium Filtration, deep-sand-bed, home-aquarium, marine-aquarium
The Bacteria’s Role In The Nitrogen Cycle
April 8, 2008
In the marine aquarium, be it a reef tank or a fish only aquarium, the nitrogen cycle is of paramount importance. It is the life support function for all the livestock. Without it, or with a serious deficiency, the livestock will be in serious difficulty and face death.
In an aquarium the livestock carry on with their normal life functions and need feeding. This introduces waste into the seawater. In addition, algae etc can die and rot. The product of the breakdown is ammonium (NH4+). Because seawater is at a fairly high pH (around 8.3) some of this ammonium is present in the form of ammonia (NH3). That is the problem, ammonia.
Ammonia that is present even in small amounts is toxic - deadly - to aquatic life. Fish can display ammonia poisoning by peculiar swimming: Swimming slowly and rolling over, going up and down in a random fashion, breathing very quickly, lying at the bottom, floating around at the top etc. Varied, but if seen there can be no doubt something is wrong. If only one fish is behaving strangely, and the rest are normal, the problem is unlikely to be ammonia poisoning.
Nature is ready to deal with the problem, luckily for us aquarists. There always seems to be some kind of life that is ready to use up whatever is available, and with ammonia this is the case. The life forms are Nitrosomonas bacteria. The ammonia is used by the bacteria for energy.
So that’s fine then, problem solved. Not quite. Even though the bacteria mentioned have removed ammonia, it hasn’t been conjured into oblivion. Guess what, the ammonia has been converted to nitrite (NO2) which is nearly as toxic as ammonia. Fish reaction to nitrite is similar to ammonia.
So what we have is a cycle, as in the heading. More bacteria use the nitrite, these bacteria being Nitrobacter. The situation becomes much better after this stage, as the product produced is nitrate (NO3). This is nowhere near as toxic as ammonia and nitrite, but can cause some problems at high levels. Probably the major problem that aquarists could face with nitrate at lesser levels is excessive algae presence.
Nature however can once again come to the aquarist’s aid because, yes that’s right, bacteria can deal with the nitrate. Hang on a moment though, there’s a qualification here. It depends on the bio-filtration being used (the bio-filtration is home to the different bacteria). If the aquarist is using live rock, fine, good quality live rock in proper quantity will deal within reason with nitrate. If the bio-filter is a canister, for example, then there aren’t any bacteria present to deal with the nitrate. Why? Because the environment is oxygen rich. To deal with nitrate a nil to low oxygen environment is required. Live rock can provide this as the bacteria involved live deep inside. If the example a canister filter is in use then other means are available if required to control the nitrate.
The nitrate is removed because the bacteria extract oxygen from it, this being the only way open to them. The end gas, nitrogen, is released from the seawater at air/water interfaces.
So the whole nitrogen cycle is from ammonia to nitrogen gas. There are several ways to achieve the cycle, but whatever method is chosen (except perhaps one) there are important points for the aquarist to be aware of.
The bacteria colonies that convert ammonia to nitrite use a lot of oxygen in the process. The next stage, nitrite to nitrate, uses up a lesser amount. There is only one place that the oxygen can come from and that is the seawater. In addition to the bacteria, the reef livestock need oxygen in good quantity. So the seawater must always have a good oxygen content. Having said that, the modern reef or fish only system usually hasn’t a problem, as they are mainly open topped, often use weirs, and have good water circulation, particularly reefs. If oxygen content were ‘near the edge,’ it could be more of a problem for a fish only system because of the usually higher fish stocks per gallon. What is the possible exception mentioned in the previous paragraph? The trickle filter. Seawater is exposed to the air as it runs down through the media, which means oxygen from the air could be used (an air/water interface).
The nitrogen cycle bacteria are not present instantly. With ‘unnatural’ filters, such as the example a canister, they are introduced by inoculating the seawater with the required substances. Commercial preparations are available. Measuring the seawater for ammonia, nitrite and nitrate advises the aquarist when the bacteria colonies are working. Live rock is different, as the required colonies of bacteria should be present. Caution still has to be exercised as these colonies might have been diminished in the ocean to aquarium processes.
There isn’t any argument - the life support system, or bio-filter, or nitrogen cycle, call it whatever, must be present and effective. It will then protect the livestock by working unseen and silently.
Tags: aquarium, Aquarium Filter, Aquarium Filtration, Equipment, live-rock, nitrogen cycle
Should You Use Cured Or Uncured Live Rock?
March 15, 2008
Live rock has become a widely used media for filtration. It is a natural way to filter and it deals, within reason, with the full nitrogen cycle. It is suitable for all marine aquarium systems, and is usually very successful if the quality and quantity are correct. In addition, it is an excellent aquascaping material, lending itself very well to rock formations (well, that‘s not really surprising is it!).
Seems the thing to use then as far as filtration and aquascaping are concerned. Properly used there aren’t any real drawbacks. There is one drawback though, and that is cost. Most aquarists use rock that has already been cured, as it is more convenient (I hate to use the word ‘instant’ in a hobby where patience is so important) and just pay the premium.
Why the cost? As the media is rock, it is bulky and heavy, though the weight does vary. Therefore the air freight costs are high. Many an aquarist could be taken aback by the potential bill for sufficient quality live rock.
Is there any way to reduce this cost? An obvious way is to use a different filtration system, such as a canister or trickle filter. These are not as efficient in bio-filtration as live rock as far as the coverage of the nitrogen cycle is concerned. In addition of course, rock still has to be purchased to decorate the aquarium though it will be a lot cheaper.
There is a way to buy live rock that is notably cheaper, and that is to choose uncured live rock. Live rock is cured often by the retailer, and this time and effort, plus the equipment needed to achieve it, has to be paid for.
‘Cured’ live rock! What happens, is it injected with a special medication or something? No, it simply means that time is given for the life on the rock to die off, so that the aquarist can put the rock to nearly immediate use.
Live rock is collected from around the reefs, and consequently has all sorts of growths on it. These life forms have varying degrees of toughness, and a great many succumb to the rigours of transportation and changes of environment. Those that are left could add to the interest of the display aquarium (or not, depending on what they are!).
It is the loss of life that is of concern. It is well known that ammonia and nitrite are toxic to aquarium life and need to be avoided. As the dead life forms on and in the rock rot, and those that are dying eventually rot, toxics could reach high levels. This would be death to aquarium livestock. Therefore the rock needs to be given time in a suitable environment for this cycle to pass. Some life forms may die in the curing process because of the high toxicity.
The retailer will have tanks that are used purely for curing live rock. They will be fitted with efficient protein skimmers and the rocks will be covered with seawater. In addition there will be good circulation present, and the temperature will be maintained at an appropriate level. As time progresses, the ammonia and nitrite cycle will pass, though this period could be quite protracted. It is this that the retailer is watching for, testing to ensure that it is clear. The rocks are often then rinsed in clean heated seawater, checked and put up for sale. The rock is considered as cured.
So how does this assist the aquarist? There aren’t any additional aquariums (usually) for doing the curing process. There is only one place it can be done, and that is in the eventual display aquarium. So let’s look at that.
The aquarium is 2/3rds full of seawater, at the appropriate specific gravity (SG) and temperature. If the rock is going to eventually permanently stand on a supporting grid then this must have been completely organised before water goes in. The rock is not put into the aquarium in a decorative way, just put in. Before this, the rocks are carefully inspected for any obviously dead or dying and rotting life forms, which are removed as efficiently as possible. Some aquarists actually scrub the rock in warm seawater, but this may damage desirable life forms on the surface that might have survived. If scrubbing is done, a separate container is used - a large bucket or whatever - to keep scrubbed off items out of the main tank. As the rocks go into the aquarium, so the water will rise. If too much water is present, then it can be removed. If otherwise, it can be topped up.
Apart from heaters, the aquarium should be fitted with seawater circulators. These will be required when the display proper is ready so does not represent an additional expense. An efficient and appropriately sized protein skimmer should be switched on, again this will be required anyway. During the curing process, the protein skimmer should be regularly checked and cleaned when necessary (as when the display tank is properly functional) so that its efficiency is not reduced.
It will take time for the curing process, often counted in weeks. Any ’rubbish’ seen on the water surface or in the lower areas of the tank should be removed as far as possible, a fine net is useful for this. Also watch out for unwanted hitchhikers, such as crabs, mantis shrimps etc. though it is likely they will not be seen in the pile of rocks.
The aquarist should have three test kits available (again not an extra expense, they are required when the display tank is being stocked to monitor water quality). The kits are ammonia, nitrite, and nitrate. At first, after say three to five days, ammonia is checked. When this is detected, in the following period it is likely to rise. This can be monitored, and checks for nitrite commenced. It is not necessary to check every day, but when ammonia ceases to rise and begins to fall or disappears, nitrite checks can be done more regularly. Ammonia is at the front of the nitrogen cycle, and bacteria convert this to nitrite. Therefore if nitrite is present it shows that the initial bacteria battalions are at work. Nitrite may continue to rise, then start to fall or disappear. At this point check for nitrate, as this is the next to appear in the cycle. Nitrate could continue to rise to quite a high level, but should level out. This indicates that the nitrogen cycle is effective and has converted all toxins (ammonia and nitrite). Is this the end of the story? As far as the nitrogen cycle is concerned, the answer is no. Live rock is able, within reason and with time, to convert nitrate so that it can escape from the seawater as gas. It is best to let the nitrate fall a little, showing that nitrate conversion is in progress. The live rock is now nearly ready for use.
There should be available an amount of freshly mixed seawater, of the same SG and temperature as that in the tank. The amount should be equal to the largest volume that can be stored, say 20% or more of the tanks gallonage.
If necessary, lay a waterproof covering on the floor which is large enough to hold the live rock. The live rock can be piled up if necessary.
Remove each piece of live rock from the tank, giving it a rinse by moving it back and forward. If the following is going to take a little time, then the rocks can be covered in seawater dampened newspaper.
Siphon out some seawater, making sure that any debris is removed. Continue siphoning until the seawater removed is a little less than the new stored seawater. This can be done by measuring it out with a known volume bucket. This seawater is going to be thrown away, but keep the last bucket.
Now is the time to put in the decorative sand bed (pre-cleaned sand) if any. The live rock can now go back in, aquascaped as the aquarist desires. The water level will again rise, but be short once all the rocks are in. The new seawater can now go in. If the water level is a little low, use some from the bucket that was kept. Once at the desired level in the tank, all old seawater can be thrown away.
A check should be made that the heater(s), circulation devices and protein skimmer are in position and switched on.
The tank can be left for 24 hours, then the aquarist can do another ammonia, nitrite and nitrate test. Ammonia and nitrite should be undetectable. Nitrate is likely to be present. The guideline target for a reef tank is 10 ppm (parts per million) or less. If it is higher than this, the aquarist has two choices - wait and see if the bacteria in the live rock reduce it (this takes time) or do a further water change. The level above that desired will assist in the decision.
So the aquarist is now ready for stocking. One of the good things about curing is the high ammonia etc that is likely to arise, which means there is fuel for the bacteria - which means that the bio-filtration should be ready for livestock. However, this cannot be taken for granted and checks of ammonia and nitrite should be made as the display is slowly stocked. Nitrate needs to be monitored too.
It will be interesting as the age of the display increases to observe what life actually appears from the live rock. It could be various types of algae, small worms and the like. The aquarist will have introduced perhaps the best bio-filtration available, reduced the cost considerably, and, all things being equal, should end up with a wonderful marine display.
Tags: Aquarium Filter, Aquarium Filtration, live-rock, marine-aquarium, reef-tank, saltwater-aquarium
How To Tell When Your Aquarium Has Cycled
March 7, 2008
A great deal of fun and excitement is caused by the planning and building of a new marine aquarium. All the equipment to consider and choose, and the controlled excitement of when the first live stock will appear.
Provided the aquarist has chosen and set up the equipment with care, then there isn’t any reason why the fish only aquarium or reef aquarium should fail. Except one!
If the aquarist has researched the following will be known, but it is surprising how many problems arise because of missed or inadequate preparation in this area. The worse scenario is the death of livestock that have been so eagerly anticipated. Yet if this final step had been completed properly the story would have been very different.
The final step is the maturation of the biological filter. This is the filtration that completes the nitrogen cycle, or some of it. Toxics that are lethal are removed (ammonia and nitrite) by the aquarist’s good and hardworking friends the bacteria. These bacteria do not just appear however, they need to be introduced and develop in most cases.
For example if the aquarist has decided to use a trickle or canister filter then the necessary bacteria will be totally missing. Put fish in now and..well, I’ve already mentioned it.
I’m against using hardy fish to start off the filtration, both on ethical grounds and because these fish can be a problem later - they are often aggressive and quarrelsome. So I like the use of a commercial fluid, easily obtainable, to kick start the filter. Full instructions are given and should be followed. The bacteria will appear and develop, first dealing with ammonia and then nitrite. The aquarist needs to monitor the levels with a test kit.
What of live rock? Live rock comes with bacteria, ones that can deal with ammonia and nitrite, and also (unlike canister and trickle filters) nitrate within reason. So no problem then? Hopefully not, but it must be remembered that live rock has gone through processes, often at the retailers, before it is sold. Much of the life on the rock will have died, and it is possible that the bacteria populations may have been reduced too. This raises the possibility that they cannot deal with a higher bio load straightaway.
Live rock when it is being ‘cured’ often sits in water that has a lot of ammonia and nitrite present because of the die off mentioned. This should mean that the bacteria populations have been maintained. This is not necessarily so, however. When buying live rock it is always prudent to ask how long the cured rock has been in the ‘for sale’ tank at the dealers. If it has been there for say a week or more the aquarist should not assume the bacteria are fully ready for work.
So back to the question - knowing when the bio filter has initially cycled.
If the aquarist is to use a trickle or canister filter then regular testing of the water for ammonia and nitrite should be done. Sometimes the maturation fluid instructions advise to test for nitrite after a given period - this is because nitrite is the follow-on from ammonia, so its appearance shows that the bacteria that deal with ammonia are present. The nitrite will itself disappear (leading to nitrate) meaning that the bacteria that deal with this are present. The bio- filter is now initially mature. A water change and the slow introduction of fish can proceed, always using caution and checking routinely for the presence of toxics.
Good quality live rock that is newly matured (ie. has been matured within a week) can be assumed to be ready to handle a bio-load. Fish stocking can commence slowly, checking routinely for the presence of toxics.
The same can be said for live rock that has been matured for more than a week - stocking can be commenced slowly. In this case though, more caution is needed as the bacteria populations may need time to adjust to the bio-load. Remember that the longer the period of time since the rock was cured the more the bacteria populations will have diminished - as with all living things they need food. It is important to check daily for the first week or two for any presence of ammonia and/or nitrite. Checking continues after this but does not need to be so regular.
With any system that is using live rock for filtration, it is important that sufficient good quality live rock is present. Live rock affords great filtration, but one rock in a fish tank is going to fail!
The bio-filter, whatever type it is, could also be called the life support system. Without it, or if it is too immature, livestock will have problems or die. As the bio-load slowly increases the bacteria will need to adjust, and time must be given for this The bio-filter will not be fully mature until all the livestock have been successfully introduced and are demonstrating health and vitality.
Tags: Aquarium Filter, Aquarium Filtration, home-aquarium, marine-aquarium, saltwater-aquarium
Live Rock - How Much Do I Need?
February 28, 2008
Live rock is so called because it bears some of the tougher life forms that have survived the processes between the wild and the dealer’s sale tanks. In addition it harbours beneficial bacteria that are able to deal with ammonia, nitrite and nitrate.
All marine aquarists can use live rock. It doesn’t matter if it is a seahorse, fish only or reef aquarium. Live rock of good quality will be beneficial and decorative.
Live rock is expensive, which is understandable, as it is transported by air. Therefore aquarists should consider buying different grades: base rock, which doesn’t show much on its surface and is suitable for the reef base, and premium rock which can be used to cover the surface of the construction. This reduces the cost up to a point.
Once the aquarist has reached the live rock purchase stage, how much should be bought? In a reef tank there is obviously going to be a lot, and the aquarist knows the extent of the reef that is to be constructed. What of a fish only or seahorse tank?
The usual guideline is to use 1½ lbs for each gallon of seawater in the whole system. This is fine - but there are different types of live rock, some quite heavy and some quite light. So what to do?
In the reef system, as already said, the aquarist knows the extent of the intended captive reef. Therefore it is simple, as enough rock will be needed for that construction. Captive reefs are usually 1/2 to 2/3 of the display tank volume. As the reef system holds a smaller fish load to protect water quality, this amount of live rock should be enough. Corals present a very small bio load. Many if not most reef systems employ a sump and deep sand bed so the filtration is more than likely to be adequate. A decent protein skimmer is necessary.
The seahorse tank is similar. Though a reef is not to be constructed, enough live rock to construct a decent decorative pile or two should be purchased. The bio load on these tanks is usually low, as seahorses are not compatible with fish (except pipefish), and, provided routine water changes are done, very often a protein skimmer is not used, though a protein skimmer can be fitted. Seahorse tanks are usually quite small and water changes are not a problem. In addition, Caulerpa macro algae is often grown in the display tank, and this will assist with water quality and make the seahorses feel more at home.
The fish only tank needs caution. This is because these systems are likely to carry a higher bio load, in other words more fish can be kept than in a reef system. The aquarist is not going to keep a reef tank, and may decide to only purchase a little live rock. If this is the case, then additional bio-filtration must be employed, even if this is a canister filter filled with appropriate media. With live rock as the main filtration, the aquarist will need to use a substantial amount, approaching a reef system. In addition, a sump with a DSB would be a great help. An efficient protein skimmer is a must.
Once any of these types of system are set up with live rock, the aquarist must monitor the water parameters for ammonia, nitrite and nitrate, particularly in the early months (this is in addition to the other parameters that are monitored with a reef system). Bio-filtration needs to settle and adapt to the load it has to deal with, so stocking needs to be done gradually with patience.
Setting up a marine aquarium is not the cheapest of activities, and in the future the system is going to hold life. It makes sense therefore not to cut corners with an absolutely necessary part of the system, the life support filtration.
Tags: Aquarium Filtration, Equipment, home-aquarium, marine-aquarium, saltwater-aquarium
At What Times Should The Lighting Be On Above The Refugium
February 15, 2008
In the refugium we are attempting to grow macro algae. The reason for this is that as they grow they remove nutrients like nitrate and phosphate out of the water.
In a previous post I have discussed what type of lighting should be used so that you can get optimum algae growth plus I have also talked briefly about harvesting the algae from time to time.
One thing which I have not really touched upon is how long you should provide lighting for.
There are two methods available - one which I agree with and one which I don’t.
I shall cover the one that I don’t agree with first.
Option 1 - Provide Lighting Over a 24 Hour Period.
So why don’t I agree with this?
Basically it’s because it does not happen in nature. There are some aquarists who believe that providing lighting over a 24 hour period prevents algae crashes from happening. This is where all the algae suddenly dies and all the nutrients which are removed are released back into the aquarium.
To me this has never been proven. If you look at nature the algae beds in the sea are exposed to sunlight over a determined length of time. The same as provided for the corals. You would not leave your lights on for 24 hours to provide light for the corals so why do it for the algae.
I am firmly of the opinion that we should attempt to replicate nature wherever we can. It works in nature so why try to change it in our aquariums?
I also believe that the algae needs a rest!
There is another factor to this as well. This is that in darkness the micro organisms come out more and start to feed and reproduce. It has been noted by many aquarists that they have experienced a pod explosion when the lights are out for a length of time.
Option 2 - Provide Lighting Over A Shorter Period.
This is my preferred option.
I have covered some of the reasons above. i.e. lighting is not provided over a 24 hour period in nature so why do it in our aquariums and the factor of the little critters which we are providing refuge to.
So how long is a shorter period. Well it can be many things but the method I use is that the lights above the refugium turn on when the main lighting turns off above the display aquarium - i.e. the metal halide lighting. They stay on all night and turn off when the metal halides turn on the next day. This is sometimes called reverse sunlight lighting.
So why do I do it this way and not have them on at the same time as the metal halides?
Basically this is so that I do not experience a drop in pH over the nightime hours. The reason this happens is that when the lights are on photosynthesis occurs, carbon dioxide is used and oxygen given off into the aquarium and the pH rises or in this case remains stable.
Stability as we all know is a major factor we are all hoping to achieve.
If we had the refugium lights on at the same time as the main display aquarium when all the lights went off there is a possibility that the pH will drop.
So that’s why I prefer option 2 - it simply makes sense to me.
Another thing that I also do is occasionally turn off the lighting above the refugium for a couple of days. I have found that when I do this I get a lot more ‘critters’ in the refugium. The more ‘critters’ there are the happier I am!
Tags: Aquarium Filtration, Aquarium Lighting, Equipment, macro-algae, marine-aquarium, refugium
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