Oh, no, nitrate…

…and I don’t know why. I’ve live rock and everything seems fine at the moment, but I’m worried..

These words are quite understandable. Over and over again mention is made of seawater quality and how important it is - in fact seawater quality is the number one requirement, ahead of lighting (for a reef aquarium). So concerns in this direction are quite correct.

First, without being over scientific, what is nitrate? Every aquarium in order to be healthy needs a biological support system, commonly called a bio-filter, though some aquarists call it aquarium life support. This filter when functional is loaded with bacteria. The life processes of livestock and the rotting of uneaten food, algae and the like creates toxins, the first of which is ammonia. This is deadly to livestock. Bacteria within the bio-filter convert the ammonia to nitrite, again nitrite is a toxin and nearly as deadly as ammonia. Other bacteria then convert the nitrite to nitrate which in general is not toxic, but detrimental to seawater quality at too high a level. The bacteriological process has the overall title of ‘The Nitrogen Cycle.’ This cycle under certain conditions continues when nitrate is converted to gas which escapes from the aquarium, but here the concern is nitrate.

In the aquarium, whatever type it is, ammonia, nitrite and nitrate are being continually produced. The production is at its highest in a fish only system, as fish consume relatively large amounts of food which enters the Nitrogen Cycle process. Reef systems have lower fish loads, but nevertheless the same applies. The bacteria are continually hard at work.

The guideline that is given for nitrate when tests are being done is 10ppm (parts per million) or less in a reef system, and as close as possible in a fish only system. Why ‘as close as possible?’ It is more difficult to maintain a low nitrate presence in a fish only system because, as previously stated, there is a higher fish load and consequently heavier feeding. Why is the level stated more strictly for a reef system? This is because there are corals present and these are generally more sensitive to nitrate than fish. Note that some fish are more sensitive which should be noted in research before purchase.

Just to wander off the point a moment, there is something else that is interesting as well. I have never encountered this problem. A good while ago a well-known aquarist was asked in a magazine why a recently purchased fish, stated by authorities to be ‘reasonably hardy’, on introduction to a fish only system died. All the other fish present, some considered to be less hardy than the new addition, were fine. After a considerable amount of head scratching, it transpired that the nitrate reading in the seawater was approaching 150ppm. A little high in anyone’s book! There wasn’t any mention of problem algae which was fortunate for the aquarist. The fish that were already in the aquarium had been there from the word go or a little later. It was also discovered that seawater changes were done very spasmodically. So why did the new fish die? It had been purchased from a retailer whose seawater quality would have been at least reasonably good with low nitrate. The fish had then been introduced to very polluted seawater and had succumbed. What of the other fish? These had been in the aquarium for a long while and the nitrate level would have risen slowly. So they had become accustomed, or perhaps it is better to say ‘hardened’, to the nitrate presence. The advice was to carry out regular seawater changes and bring down the nitrate level, but not too quickly in case of any affect on the resident fish.

I bet that problem doesn’t happen very often. Anyway, back to the text.

There’s nitrate present - what to do? If the nitrate is within the guidelines, then perhaps it could be lowered even further by a small increase in the amount of seawater changed at routine changes. It is when it is quite high that is of most concern. The seawater needs to be of high quality and there isn’t any desire to tempt fate by providing nourishment for nuisance algae.

The first action is to attack the problem by, as just mentioned, increasing the amount of seawater changed. The basic general guideline for routine seawater changes is 10% of the net gallonage in the whole system but this can be flexed according to need. It is best not to increase the amount above 25% (severe cases) as the ‘raw’ seawater in this quantity isn’t always happily received by livestock. Increasing the amount changed increases dilution. The level should come down slowly until it is acceptable. The continuous addition of food and presence of livestock means that the Nitrogen Cycle is ever active (as it must be), so routine seawater changes should continue. After the following, if a cause of excessive nitrate is found the amount of the changes could be reduced again.

The above is treating the effect but what about the cause? It is best to start from square one and work through. There isn’t anything difficult in the process.

Excessive nitrate is in the seawater, but could it be getting in before any seawater enters the aquarium? First, have a look at the dry salt mix in use. It would be unusual with modern salts for there to be any nitrate (or phosphate) presence, but check that this is so by looking at the manufacturer’s information. Often the dry salt package will advise the salt is nitrate and phosphate free. In the unlikely event it isn’t free of these pollutants, change the brand to one that is.

The dry salt has obviously to be mixed with fresh water before use. It is highly recommended that RO (reverse osmosis) water is used, which is tap water that has been ‘super filtered’ to remove any unwanted substances. If RO water is in use, do a nitrate test to see if the unit is functioning properly. If there is a nitrate presence, then the heart of the RO unit, the membrane, may have a problem, and this should be checked. It may mean the purchase of a replacement unit.

If tap water is in use and not pre-filtered, then the same thing applies - test the water. In some areas tap water is fairly pure with a very low nitrate content, but in other areas it may not be. These areas are often agricultural where there is a lot of fertilizer in use (including nitrate), or industrial. If it is found that there is a nitrate presence, particularly a fairly high one, then it is best to invest in an RO unit and be rid of the problem. There isn’t much point in introducing nitrate when fresh seawater is mixed after the manufacturer has taken the trouble (which the aquarist pays for) to ensure the salt is nitrate free.

The next checks concern the aquarist’s husbandry disciplines. The aquarist can quite easily be over or under enthusiastic in some areas.

The first area to consider is feeding, where the majority of new aquarists overdo it. Overfeeding is fairly difficult to avoid by an experienced aquarist, as it is hard to ensure that all food goes where it is intended. The new aquarist is often over-anxious that the livestock get enough to eat and consequently too much food gets into the system, much of it is not eaten, it rots and joins the Nitrogen Cycle. This cycle as already stated produces nitrate. As a point of interest, as with nitrate, phosphate is linked to nuisance algae outbreaks. Guess how the majority of phosphate gets into the seawater - yes, with food. So it is very important not to overfeed. There are a few guidelines on feeding techniques to look at, including one under ‘Articles’ on this site titled ‘Food For Thought.’ Allowing a little time to learn how to feed and ensure the fish have enough, and at the same time avoid overfeeding as far as possible, is very worthwhile.

The second discipline that needs to be looked at is maintenance. Some aquarists like doing this (as some gardeners like weeding) and some do not. I don’t completely enjoy it, but do it willingly because the appearance of my reef, meaning the health and vitality of my livestock, depend on it. So how does maintenance have any effect on nitrate?

Good seawater circulation usually means good oxygen content. Oxygen is taken in at air/water interfaces, particularly the seawater surface in the aquarium. If circulation is at it should be oxygen content should be adequate. The bacteria that convert the toxins ammonia and nitrite are very reliant on oxygen availability in the seawater, so if there is plenty always available then the bacteria are able to function efficiently. This produces nitrate as previously mentioned. If live rock is used in the aquarium, and the oxygen loving bacteria are producing nitrate, then the nitrate converting bacteria convert it to gas, which easily escapes from the aquarium because of the good circulation. So the aquarist needs to ensure that circulation is adequate. Lack of good circulation could be a design error in a new aquarium, or in an established one the result of coral growth blocking seawater flow, or powerhead intakes being clogged with detritus, or tubes becoming narrow with detritus build-up. Checking these is part of ongoing maintenance. Intakes can easily be checked visually and the inside of tubes occasionally - seawater output, or the lack of it, could indicate tube blocking.

Detritus itself is a normal entrant to the aquarium. When maintenance is being done detritus should be removed as far as possible. This removal helps prevent rotting substances from entering the Nitrogen Cycle in the first place, thus not producing any additional nitrate. If detritus is heavy an investigation should be made to find out why and hopefully remove the cause. Seawater circulation usually means that detritus tends to settle in one or two particular areas, usually where the flow is lower. When a routine seawater change is done this detritus should be siphoned out.

Detritus can also settle like a dust on live rocks, or any rocks for that matter. It is a good idea to remove it once in a while. How can that be done? Obtain a baster (as used in a kitchen) or similar and gently pump seawater over the rocks. This will put the detritus in the seawater column and hopefully permit either a mechanical filter to extract it, or make it settle in an area where it can be siphoned out.

Another area to check is a sand bed. This sand bed could be in the display aquarium or in a sump, though in this case the sump is unlikely - unlikely because the sand bed here is one for decorative purposes only which would not normally be in a sump. The decorative bed is usually 1 to 2″ deep and made up of coarse coral sand. They can be very attractive. They can also get very dirty, as detritus settles into the sand bed between the grains. This is unwanted and the detritus should be removed by using, for example, a gravel cleaner on a reasonably regular basis - at least when the sand starts to look dirty. A dirty sand bed is not attractive anyway so the aquarist should notice it. (Note that only a decorative sand bed should be cleaned, not a DSB (deep sand bed))

Finally, nitrate can be produced in excess by the livestock, particularly fish. Not directly of course, but because of their life functions and the food that has to be offered. So it is important not to overstock - the more fish the stronger the pressure on seawater quality. More fish, more food and the harder the bacteria work. Normally they’ll do their job well, and normally they’ll work 24/7 on everything suitable and available.

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Tags: Aquarium Maintenance, Care, Equipment, nitrogen cycle, phosphate, Water Quality

Algae - It Makes A Lot Of People Give Up

Thousands upon thousands of potential aquarists make the decision to start a saltwater aquarium, be these fish only or reef aquariums all around the world. Unfortunately a lot of these aquarists ultimately give up in this amazing hobby.

There are many reasons as to why people give up. This could be personal finances, time, knowledge and many more, however a prime candidate unfortunately is algae.

Algae in the aquarium can look nice however in time this once ‘nice looking’ algae can turn into a pest and make the aquarium look unsightly. Before long the algae starts to cover the rocks, the sand, the glass and more. Every effort is made by the aquarist to clean this up perhaps by manually removing it, performing water changes, checking the water parameters, researching the possible causes etc however once one algae bloom is sorted before long another one may appear.

I appreciate that at this time the aquarist may become disheartened. I know I have been through this stage and can honestly say that algae blooms are a pain.

When people look into starting a saltwater aquarium they imagine an aquarium full of corals and fish which are so striking in colour and movement that the appearance of this unsightly algae is new to them. It is not what they wanted and try as they might it simply will not go away.

First to come may be a slight brown dusting of algae initially over the sand, second may come what looks like slime over the sand, perhaps the rock, after this long hair like algae may appear on the rocks and glass. Later algae which look like balls may appear!

It’s no wonder why aquarists consider giving up when the dream of a spotless saltwater aquarium is suddenly flawed with dirty looking algae!

Each of these different aspects of algae feed upon a different type of nutrient in the water. The trick to understanding how to clear the aquarium of the nuisance algae is to understand what it is feeding upon.

This is where the hard part starts. The reason for this is that since the algae is feeding upon a certain nutrient or nutrients in the water then a water test may not how this parameter as being a problem. A good example of this is phosphate. Phosphate is a common food for problematic algae however when a water test is performed the result is ok. This could be because the algae does not feed upon this type of nutrient or it could be that the algae has removed enough from the water for it not to show up on a water test!

The best thing to do if you encounter an algae bloom is determine what type of nutrient the algae is feeding upon and then remove its food source. For example if you have algae which is long and wavy then this is probably hair algae. Hair algae likes to feed upon nitrate and phosphate. In this example the best thing to do is attempt to reduce the nitrate in the aquarium by checking your feeding regime and increasing the amount of water changes performed to dilute the nitrate in the water column. To reduce/remove the phosphate levels it would be beneficial to introduce an element of phosphate remover for example a product like Rowaphos.

If you remove the food that the algae feeds upon then the algae bloom itself will reduce.

At the start of an aquariums life you need to remember that everything in the aquarium is new. All the pumps/powerheads will probably not have been submersed in water before, the sealant is new, the sand will be straight from the bag, the water will be sterile etc etc. From some of these certain elements may become evident in the water. A prime example of this is silicates from the sand - the slight brown dusting you see over the glass and sand is quite often caused by this. This aspect of algae quite often feeds upon silicates and will exist until its food source is exhausted.

I have seen aquariums entirely coated in this type of aquarium simply clear up overnight purely because the food source has gone.

In this example the silicates from the sand becomes exhausted and therefore the brown dusting disappears perhaps never to be seen again. In other areas if the aquarists is not diligent and does not perform the correct care and maintenance post identifying the food source then the algae blood can and perhaps will re-occur. There is no point in locating a problem, resolving it simply to allow it to raise its ugly head again.

The majority of aquariums when started do go through various algae blooms. This is the aquariums ways of becoming settled. Within time if the aquarist is patient and performs the correct care and maintenance then the blooms will slowly subside - hopefully never to appear again.

For all you new aquarists and the aquarists who are currently attempting to deal with an algae bloom I and many other aquarists understand what you are going through right now. The two things I can say is be patient and identify the bloom you are having issues with, identify its food source and eliminate it.

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Tags: Algae, Aquarium Maintenance, Care, Equipment, nitrate, phosphate

Nitrate - The Ongoing Problem

I answer numbers of questions concerning various aspects of marine aquarium keeping. Looking at the subjects of all these questions it seems one of the biggest problems that is faced by aquarists is excessive nitrate (NO3). If it is not a problem the subject seems to puzzle some.

It may be thought that I tire of the same question, but this is not so. Rather, I am pleased as it shows that aquarists are concerned about the welfare of their livestock and wish to understand how the problem could have arisen and how it could be dealt with.

Why are aquarists so concerned about nitrate levels? Probably because, along with phosphate (PO4), it is a known nutrient of nuisance algae, the horrible stuff that can show its ugly presence under certain circumstances. In addition, corals will tolerate nitrate badly in many cases, and in a lesser way the same can apply to fish.

I hope I will be forgiven for not repeating what is already in other articles on this website (or maybe I’m just lazy!). What I have done is note in brackets any relevant article and the path to it.

To get to ‘Articles’ simply click on the word at the top of the page or click the link.

First of all, nitrate is not a disaster in itself, in the way that a presence of ammonia (NH3) or nitrite (NO2) could be. Nitrate is a product of the so-called Nitrogen Cycle (see article ‘The Nitrogen Cycle‘ under the sub-heading ‘Filtration‘). The nitrogen cycle should be understood by all aquarists and is straightforward.

Nitrate will be produced in any marine system, the level being dependant on more than one factor - these include type of system, stocking level, and bio-filtration method. In addition, husbandry expertise should be included. Excessive nitrate levels are usually faced by new aquarists where experience has not had time to accrue, but the problem is not entirely restricted to the beginner.

First of all, how much nitrate is acceptable? There are guidelines of course, but it should be noted that an inability to meet the guideline does not mean disaster. However, a continuing effort to control the nitrate level to the guideline should be made (see article ‘Guideline Water Parameters‘ under the sub-heading ‘Water Quality’). For nitrate in a reef system, the guideline is 10ppm (parts per million) or less, and in a fish only system the same if possible, or as close to it as can be achieved.

It has been said that ‘the answer to pollution is dilution.’ This is correct for nitrate and the marine aquarium. Routine seawater changes should be carried out whether there is a nitrate presence or not, and the guideline is 10% of the total net system gallonage per week. This can be flexed somewhat according to need, but gives a base for a newcomer. In a well designed system that is not overstocked this in itself could be sufficient to control nitrate levels, where there are no other controls present.

To help prevent unwanted pollutants including nitrate getting into the aquarium, it is highly recommended that reverse osmosis water (‘super filtered’ tap water) is used. An aquarist could be surprised at the content of tap water (see article ‘Reverse Osmosis‘ under the sub-heading ’The Basics‘. Also see article ‘Should You Use Tap Water?‘ under the sub-heading ‘Water Quality‘). Reverse osmosis water should be used for the initial aquarium fill if possible, and also for evaporation top-ups and routine seawater change mixes.

The marine system should not be overstocked. Proper stocking allows for high water quality which by definition is lacking in nitrate (see article ‘Stocking The Salt Water Aquarium Part 1‘ and also Part 2 under the sub-heading ‘The Basics‘).

How does the type of filtration help?

If the aquarist is using live rock of sufficient quality and in sufficient quantity, this excellent filtration can deal with nitrate as it completes the full nitrogen cycle, the nitrate being released from the aquarium after conversion to a gas. This is ideal, of course, but the aquarist must be sure not to overload the filtration with fish.

If another bio-filtration type is in use, for example canister filters or trickle filters, then once the nitrogen cycle has reached the production of nitrate stage that is as far as it goes. Seawater routine changes and/or other methods of nitrate control are required. If the nitrate level is persistent, and is not reducing, or is even rising despite seawater changes, then there are methods to reduce it. One good introduction is to construct a DSB (deep sand bed) if possible (see the articles ‘Deep Sand Bed Construction‘ and ‘Deep Sand Beds‘ both under the sub-heading ’Filtration’).

Some aquarists who have a sump, or even utilise the display aquarium, use algae to assist in combating nitrate (and phosphate). This is the macro-algae Caulerpa (see the text ‘Caulerpa‘ - this is not under Articles, but can be found by going to the right side of the page and looking under ‘Categories’. Go down to the bottom of the list to ‘Problems’, and click on ‘Algae’, which is at the very bottom).

One point I will make here which is a repeat of what is stated elsewhere is to do with feeding. This is one of the major ways, probably the major way, that nitrate (and phosphate) get into the aquarium.

Overfeeding! Until experience has been obtained and the aquarist knows how much should be fed, it is very easy indeed to overfeed. It is often done because of anxiety as to whether the fish etc are getting sufficient to eat. Fish are very good at ‘begging.‘ The fish will often eat until they can eat no more - this is because they instinctively eat while there is food available. They do not know, as in the wild, when further food will be available. Unfortunately, when food is taken in to such an extent some can be excreted half digested which adds to the likelihood of nitrate. In addition, the aquarist can place too much food in the aquarium anyway, and the excess not taken by the fish sinks and generally rots. This leads to nitrate. It also follows that if the aquarium is overstocked then feeding is going to be excessive, and coupled with a newcomer’s inexperience which permits overfeeding anyway there is going to be even more nitrate. Digressing - in a newly set-up system this overfeeding can also put a potentially dangerous strain on the bio-filtration. (For feeding, see the article ‘Feeding Time!‘ under the sub-heading ‘Care and Maintenance’).

When it is considered that one gram (about a teaspoonful) of flake food with a protein content of 50% can convert to 336ppm (parts per million) of nitrate* then overfeeding causing a problem can be understood.

I hope that this text along with the articles noted will help to bring together the causes of, and methods of dealing with, nitrate.

(* Reference: Helmet Debelius & Hans A Bach. Marine Atlas)

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Tags: Aquarium Maintenance, Care, nitrate, phosphate, Problems, Water Quality

Remember To Harvest The Algae In The Algae Bed

In a [tag-tec]saltwater aquarium[/tag-tec] it is preferential to have both nitrates and phosphate as well as various other nutrients at the lowest possible level you can achieve.

Growing algae in the sump or in the refugium is an excellent way to remove nutrients from the water column, good examples which are nitrate and phosphate.

Once established the algae in the sump/refugium can reduce the nutrients to a very low level.

So why would you want to harvest this algae when you have spent all this time trying to make it grow?

What happens is that the algae in the algae bed, dependant upon the species being grown will grow in line with the water movement which passes through the bed. Over time the algae will form quite a dense ‘forest’ of algae – so much to the extent that a lot of the light provided will not be able to penetrate through to the lower levels.

Now you may think that this is ok as the leaves at the top will be able to grow using the light provided, however what happens is that the leaves and/or plants lower down in the sump/refugium will actually die.

When most algae die the nutrients which have been processed are released back into the water column, therefore all those nutrients which have been removed are suddenly released back into the aquarium water.

There are times when the entire algae bed dies and all the nutrients are instantly released back into the aquarium. When this happens your system will be loaded with nutrients and various problems can occur.

Therefore when you grow macro algae in your [tag-ice]sump[/tag-ice] or [tag-tec]refugium[/tag-tec] it is imperative that from time to time you harvest it.

Basically harvesting the macro algae means thinning it out.

To harvest the algae simply remove some of the algae, but do not remove any of the roots as this will prevent it from growing back. I personally use an old pair of scissors and give the algae bed a haircut!

When you harvest the algae what you are doing is removing a lot of nutrient laden plant life from the water and exposing what remains to the light provided to them. The macro algae will then start to re-grow removing even from nutrients from the water column.

Over time the algae bed will re-grow and eventually it will be time to harvest it again.

It has been noted by numerous aquarists that harvesting the algae bed the number of algae bed crashes experienced has significantly reduced.

When you remove the algae do not be tempted to feed it to the aquarium inhabitants as you are effectively feeding nutrients back into the water. Either throw it away or give it away to another aquarist who is just starting a new algae bed.

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Tags: Algae, algae-bed, caulerpa, nitrate, phosphate

Algae Blooms In Saltwater Aquariums

At various stages of the saltwater aquariums life there will be various algae blooms that will occur.

When these occur the aquarist should not feel despondant.

What you really need to do is look into why the particular algae bloom has happened in the first place. [Read more]

Tags: Algae, algae-bloom, nitrate, phosphate, saltwater-aquarium