Which Aquarium Salt Should You Use

A long time ago, before I commenced keeping a marine aquarium, seawater had to be mixed by hand using ingredients that had been individually obtained from a chemist. The hobby books of the day, and they were very few, gave details of the mix. This mix was pretty basic, and contained very few trace elements and not many of the minor ones.

As time passed a few dry aquarium salt mixes appeared which had been produced commercially. They did contain most of or perhaps the entire major, minor and trace elements. It was discovered that nitrate and phosphate were unwanted as they had become known as nuisance algae nutrients, and the salt manufacturers made a great show of how their particular salt was free of them.

Now there are many commercial aquarium salt mixes available and they all claim to be ‘the best’. The mixes are now very consistent and considerable advances have been made in trying to emulate nature’s own, the seas and oceans. Some aquarists use natural seawater, and there are anecdotal reports that they have met with success, corals being really well extended and fish healthy. Most aquarists use a dry salt mix however, as it is convenient wherever the aquarist lives.

The production of dry salt mixes has moved on as the hobby has. No longer do marine aquarists struggle to maintain their livestock as technology and knowledge have made it easier. Aquariums that would dazzle those pioneer aquarists of long ago now exist - those where some of the most beautiful fish of the wild reefs are kept, and those where a living captive reef is maintained. Proper husbandry and knowledge plus technology make it possible.

The highest priority for any marine aquarium is the quality of the seawater. This is even ahead of lighting for a reef aquarium, the close second. Low quality seawater leads to problems and there isn’t any need for it. Modern sea salt mixes go a long way to providing this quality. The aquarist needs to be aware of the parameters that are required and maintain them, with supplementary additions if and as needed and routine seawater changes.

So all the aquarist needs to do is go to the local fish shop (LFS) or use the internet and buy what is needed. Basically, yes, that’s it - couldn’t be easier. There are a couple of things to bear in mind though.

The first is that which has already been mentioned. It would be unusual for a dry salt mix to be contaminated with phosphate and nitrate nowadays, but nevertheless the aquarist should be happy that it isn’t. Most manufacturers state the fact on the packaging.

Next the type of fresh water that is being used should be considered. Some aquarists use it straight from the tap, and others use RO (reverse osmosis) water. The latter is where the tap water has been passed through a very fine filter - ‘super-filtered’ it could be called. RO is the one that is recommended as it will have fewer impurities.

If the aquarist uses tap water then what perhaps is ‘ordinary’ salt could be used. This is where the mix contains the ‘standard’ amount of calcium, for example. Tap water contains amounts of calcium (which varies according to location) and there isn’t a need to have additional calcium in the dry mix. If RO water is in use then much of the content of the tap water will have been removed and a salt mix with extra calcium could be used to ensure that the level is brought up correctly. Actually, it shouldn’t be a disaster if either salt mix type is used with either fresh water type, tap or filtered tap, but the salt mixes are there so why not use them.

Then there are the mixes, as above, that claim to be suitable for reef use, as they have extra this and that which usually includes calcium. These find favour with many aquarists.

So choosing a dry aquarium salt mix nowadays is straightforward. There are those mixes that are very well known and have been in use for years, and there are more that could be just as good but are less well known. Perhaps selecting the type that a successful aquarist colleague uses is the best route, or one that is highly recommended on the internet and in hobby magazines.

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Tags: Aquarium Maintenance, aquarium salt, Care, Equipment, reverse-osmosis, Water Quality

What Are The Advantages Of A UV Sterilizer

There are devices that are considered essential for the support of a marine aquarium, such as a protein skimmer. In addition there are necessities that are housed by man and provided by Nature. The prime example of this is the bio-filter, where bacteria have their home in, say, a canister filter. Live rock of course is totally natural.

Then there are the devices that are not considered essential, but find favour with some aquarists but not with others. One of these is the UV filter. UV stands for ultra-violet, the light that is used. The UV filter is not an exclusive marine device, but also finds use in garden ponds. It is a normally fairly long and generally cylindrical device made of plastic with inlet and outlet at opposite ends. The plastic is the outer casing - inside is a glass envelope and inside this is the bulb. Between the glass and the bulb is a thin gap of about ¾” (circa 2cm) through which the seawater flows. Ordinary glass cannot be used as it absorbs the UV light, therefore it is quartz glass.

Seawater is pumped through the device and returned directly to the aquarium or sump. As the seawater flows passed the UV light, algae in the water column is damaged or destroyed (there isn’t any affect on attached algae of course). In addition, any parasites that are free swimming in the water column are killed or severely damaged so that they are no longer a threat. It is this latter action that is mostly of interest to marine aquarists.

If there is a cyclic disease in the aquarium UV radiation could be of considerable help. Diseases of this type have a stage where the parasites are free swimming when they are searching for a fish host. If these free swimming parasites pass by the UV light, as said they will be killed or damaged and no longer a problem.

This sounds like the absolute answer to the aquarist’s nightmare. Unfortunately, it is not. For the device to be totally effective it has to be guaranteed that every single free swimming parasite passes through the UV light. If this occurred the cycle would be stopped and the disease itself would go. Sadly, this cannot be guaranteed and it is likely that, subject to the severity of the disease outbreak, a few or many parasites would attach to fish thus permitting the cycle to continue. There are rocks and quiet corners in a display aquarium and sump and parasites might well escape seawater currents - even if they didn’t there isn’t any surety that they would be drawn into the UV filter intake.

So what use is the UV filter then? It is used as an aid to health in the battle against disease. I cannot give numbers or percentages for obvious reasons, but if some of the parasites are destroyed then the strength of the disease outbreak will be reduced, because there are that many fewer parasites to continue the cycle.

As said, some aquarists use them and some don’t. There isn’t any harm in using one and some aquarists run them continuously. If one is used it could be run continuously or for a period of several hours each day, the period controlled by an electric timer.

It is important to size the UV filter correctly, and the manufacturer will give guidelines as to what is required for any particular gallonage. It is also important to ensure the seawater flow through the unit is correct as to have an effect on parasites they must be exposed to the light for long enough. Finally, the aquarist must know when the effectiveness of the UV bulb is coming to an end and again the manufacturer will advise the expected bulb life. Here a notebook is useful as it is easy to work out how many hours a day, a week, a month etc the unit runs and therefore the period of time that will elapse before a replacement bulb is required. The aquarium cannot be over-irradiated, as the UV light is contained entirely within the unit.

The UV filter is an ally in the fight against disease and the treatment of it should it appear. It is not an answer to disease however. The major effort must be in the selection of healthy livestock and their quarantine before they are exposed to the livestock in the display aquarium, and the correct care of the aquarium to maintain a high quality environment.

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Tags: Aquarium Maintenance, Aquarium Water, Care, Equipment, Water Quality

Artificial Coral Reefs - Good Or Bad?

Speak to just about anyone at all and they will know what a coral reef is in general. What about an artificial coral reef though?

Most when asked the question could make a rough guess, saying it’s one built by people or something along those lines. They may even say it’s one in an aquarium, which is correct of course, and perhaps this is the answer that many marine aquarists would give.

However the artificial reefs in mind here are those that are out in the wild. They’re man-made and, as far as able, mimic the wild reef.

The wild reef is anything from a quite small affair to the huge 1000 mile + length of the Australian barrier reef. Why should anyone wish to create an artificial reef at all, what’s the point? Nature has done a wonderful job over a very long period of time.

Creating a reef may be to enhance the wild fish etc populations in an area, and at the same time help boost tourism by giving scuba and snorkel enthusiasts something to look at. Some scuba people are qualified wreck divers and no doubt really appreciate an extra wreck or two. So there’s a ship available which is no longer economical to run or repair and is ready to be broken up. On several instances these ships, military or mercantile, have been obtained by conservation/tourism interests. They are very carefully prepared, having all oil removed plus any electrical cable or other items that could be detrimental to sea life. Once prepared they are towed to the required area and sunk.

It takes a while for life to appear on the wreck, though the period of time varies. Encrusting algae often takes a hold, and soft corals. Later, hard corals appear. It can be years before the coral population is widespread. Eventually the whole ship is covered in sea life of one type or another. This can be seen on World War 2 ships that were sunk in action in suitable areas - they’re totally covered and in many cases not recognizable as ships. Many ship parts have rotted away but the corals cover the rest and maybe even keep some together. One of the high priorities of fish is a safe sanctuary and a ship offers many hiding places from the word go - once corals are present its even better. So there are myriads of fish present of different varieties approaching the diversity of the natural reef and perhaps in time equaling it.

Another type of artificial reef is one created again for tourism/conservation but this time it is created out of rock. Some land based rock was once part of a coral reef and this rock can be transported for building the new reef. Other land based rock is suitable if it does not disintegrate in seawater and is porous so that the creatures of the reef, including bacteria, can find a home. This rock is taken out to sea and dumped until there is enough for the required reef design. Though I don’t have any figures, I would guess that this is a more expensive option than the sunken ship. Again the same process occurs, with algae and corals of various types finding a home and multiplying. The fish find sanctuary and food and make it their home.

The rock built artificial reef could be a commercial project. The new reef will produce collectable corals and fish given time, and as there wasn’t a reef there in the first place it permits a supply of livestock and at the same time reduces the pressure on nature’s own products. In addition, live rock, which is much favoured by aquarists for filtration and aquascaping, can be collected and exported. When the rock is removed it is replaced by rock which then goes through the cycle of becoming live rock.

There is an artificial reef that has been constructed out of worn out vehicle tyres. It has not been in existence for very long and it will be interesting to see how this progresses and how the reef life reacts to the unusual material. If all is well what a good way of disposing of some of man’s discarded products.

I find it difficult to fault the creation of artificial reefs whether they are ship or rock structures. With proper supervision and given the time to populate, they can only enhance livestock numbers. If used with common sense, they are also of benefit to local people who should find extra revenue from employment that has been created in the export of livestock or in the service of the local tourism industry.

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Tags: Coral Reef, natural reef

Introducing - Aquarists Online Articles

Both John and I are exceptionally pleased to announce the introduction of a new service to Aquarists Online, a service called Aquarists Online Articles.

We have recently been asked on a number of occasions if any of our articles could be used on other sites, newsletters etc. Something which we either agreed/disagreed on a request by request basis.

This did get the two of us thinking though so John and I sat down a short while ago and tried to work out what we believe people are looking for when it comes to the marine aquarium hobby. Below is what we believe this to be:

• Information
• New Equipment
• Used Equipment

Quite a simple list but believe it not it actually took us some time to come up with such a simple list especially for the information aspect as we felt this could be advice, reviews, questions etc etc.

We feel that these are now all dealt with via Aquarists Online. We feel that new equipment is covered by our sister site Aqua Compare which is effectively a price comparison site purely for the aquarium hobby. Used equipment again we believe is covered by the Aquarists Online Store which is a feed into EBay which has to be the ultimate place to purchase second hand items from.

Information is a different beast altogether and it is a term which covers such a broad area. We have the forum on aquarists online where people can ask/answer questions, the social area where a community can be built using information based upon pictures, videos etc. We have two aquarium guides that we have written - one for people interested in starting a reef tank and another for people who are interested in starting a fish only aquarium. These guides are stuffed with information - basically myseld and John dumped our brains, experiences etc down into these guides and then finally we have the blog.

The blog is where we post our thoughts, advice etc for others to read and hopefully enjoy and find beneficial. The blog is where we are the most active and we attempt to post on a daily basis. John does post more than I do as I take more of an active role behind the scenes making sure that everything is working as it should do, looking for enhancements, attemping to promote Aquarists Online etc.

One of the things we also both appreciate is that there is a lot of information available in this hobby and whilst we had a simple articles section on the site which linked to some of our articles which we felt would be beneficial we did not think this was enough. There is a lot of information available the internet is a very valued place when it comes to information. This is an area which we had not covered - we only dealt with our own articles. What was needed was a resource where all of this information could be gathered so it could be read by anyone interested and also important was the ability for this information to be shared. On top of this neither John or myself wanted the responsibility to be able to find this information ourselves. We wanted a solution where other authors could submit the information themselves.

Hence Aquarists Online Articles was born…..

Aquarists Online Articles is basically an area where important articles, reference material etc can be stored in a categorised format.

This area can be used in three ways:

1. For the hobbyist searching for information

All hobbyists have a passion for learning more and sharing information about the hobby they are involved in and the aquarium hobby is no exception. As an aquarists I am sure that there are areas which you would like to learn more about.

With Aquarists Online Articles this will over time become a resource where lots of information is held. The good thing about this is that all this information will not be from the same people - in Aquarists Online’s case John and I. There are many ways to do things in this hobby and each method may work dependent upon the configuration of the aquarium. No information, other than the ridiculous is useless information. Every little bit you learn will help you as you move along with your aquarium.

Reading information from various people in my opinion is important as you can then make up your own mind as to what is best for yourself and your aquarium based upon the information you have learnt.

Basically we believe that this area will become an area which has an abundance of information in which will be beneficial to lots of people.

2. For the author

Perhaps you own a website, are a passionate hobbyist or just want to share what you want with others. For the author of aquarium articles Aquarists Online Articles is a fantastic resource for you to use.

What you can do is sign up (free of charge of course) and submit your article to Aquarists Online Articles. You can select which category you would like your article to appear in add some text about yourself, your website etc and click submit.

What this does is submit it to our article review area where either myself or John will review to make sure that it is acceptable to be listed. Once reviewed it will become active and others can read it and benefit from it. The reason we have chosen to review all submitted articles is two-fold. Firstly for spam which I personally believe is getting worse and something needs to be done about it and secondly to ensure that the content is actually aquarium related - it would be pointless not to review them and suddenly this area gets flooded with articles which have no relation to aquarium. This would then make this a useless resource.

So, how does this benefit you as an author?

Basically it can help you in many ways. Firstly and in my opinion the most important is that you can feel very good about yourself for helping others. You never know your article could either get someone started in this hobby or prevent them from giving up.

Secondly it can do a great deal for yourself. All posted articles are assigned to yourself and you can have a photo of yourself if you so wish. If you post quality articles to this area then you will build both credibility and trust in yourself. If you own an aquarium related business then this could mean ultimately more sales. The software behind the scenes allows for both articles and authors to be rated, therefore the more quality articles you submit the higher rating you should hopefully get.

If you have a website then this is where the good bit begins. Articles can be a huge source of very important traffic. No matter what type of website you have getting traffic is one of the hardest things to get. With Aquarists Online Articles when you submit an article you can also submit what is called an Author Bio. This area is where you can say a bit about yourself, your website, your business etc. Plus a link can be provided back to your website using either keywords to increase your search engine positions or a standard hyperlink.

Anyone who has a website has the ability to be able to copy your article from Aquarists Online Articles and display it on their website, however they must take the article as it is written and also display the author bio as well. What could happen here is that one quality article which is submitted could be displayed on hundreds of websites perhaps thousands all of which have your author bio on it. With this having a link back to your website more traffic could come as well as a hopefully increase in the search engines.

With the author bio also detailing information about yourself, the author this also helps to build your name, your brand as you are gaining more exposure to a lot more people.

As said the article cannot be modified in anyway be this the title, the content or the author bio therefore you should always be given full credit for the article - something which I believe is very important.

3. For the website owner

An amount of what can be done for the website owner has been covered in the above section in relation to increasing your brand name, exposure by submitting articles to Aquarists Online Articles, submitting an author bio and allowing others to use the article on their site.

A very useful tactic to increase both exposure and traffic.

But what about the website owner who does not want to write articles but wants to display some useful quality content on their site.

Again Aquarists Online Articles can help.

Any articles can be re-printed from this section and displayed on your website. It is very important to note that none of article can be modified in any way. The copyright of the article belongs to the author plus the author must always be credited with the creation of the article.

If there is an article or more that you would like to display then simply copy and paste it from this area to your website ensuring that nothing is changed and the authors bio is shown.

This allows for more content to be made available for your visitors as well as the search engines seeing more content on your site when they visit. The more content you have the better the search engines should see you and your rankings over time should increase.

It does not need to be actually on a website however. Perhaps you have a newsletter which you distribute. Content can be used from this area in your newsletter as long as the article is not modified and the authors bio is also displayed.

It is a win-win situation. Your readers get more information to read and you get more content to use.

So there we go - Aquarists Online Articles.

We both hope that you will find this new area beneficial and hopefully you will submit some of your articles into this area. We have loaded some of our articles up and will continue to do so over time. You never know this time next year there may be thousands of articles in there - what a huge resource of useful information that would be!

Aquarists Online Articles

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Tags: aquarium, aquarium questions, aquarium-articles, aquarium-information, home-aquarium, marine-aquarium

Dissolved Oxygen In Seawater

Don’t worry; we’re not going all scientific. There’s no need to anyway, the detail the marine aquarist needs to know is straightforward.

Oxygen is a very important dissolved gas in the seawater. The livestock need it to survive as we do - no oxygen, no life. If dissolved oxygen is in short supply then the aquarium livestock will be subject to stress, and if the oxygen level is continuously too low disease and maybe death will follow.

It isn’t just the livestock that will suffer either, the bacteria in the bio-filter will too. These bacteria operate the nitrogen cycle when ammonia is converted to nitrite which in turn is converted to nitrate. The ammonia and nitrite are toxins and will kill at quite low levels, so the bacteria’s welfare is paramount. The bacteria that convert the toxins are oxygen hungry and rely on the amount available in the seawater.

In addition if there is a good supply of dissolved oxygen in the seawater the redox potential will be reasonably high meaning a clean environment. For simplicity’s sake the redox potential is a measure of ‘cleanliness’.

Oxygen is taken into the seawater at air/water interfaces, the major one being the aquarium seawater surface with more in the sump, weirs, overflow pipes (where air is also in the pipe) etc. The intake of oxygen is dependent on efficient seawater movement, and without this movement trouble could follow.

There is about twenty times more oxygen in the air than there is in seawater. Seawater in the aquarium should have an oxygen level of between 6 and 8 ppm (parts per million). The average amount for a well designed reef aquarium is 6.5 ppm*. Not a lot really, but quite sufficient if all is operating properly. This amount of oxygen varies somewhat according to the salinity and temperature of the seawater - another reason why high temperatures bring the aquarist closer to the ‘edge’. Further, oxygen levels can fall at night when the aquarium is in darkness as, for example, algae do not photosynthesize. This can be combated by having algae in a sump which has an opposite lighting cycle, that is, the algae are lit when the main display lights are off.

All aquariums, be they coral only, fish and coral or fish only should have adequate circulation and seawater oxygen levels. However, it is the fully stocked fish only system with its higher numbers of fish that could be most at risk.

Fish place the highest demand for oxygen (I do not know the demand for oxygen placed by bacteria) so it follows that the more fish the heavier the oxygen demand. There are two dangers - first, the demand cannot be met because the aquarium is overstocked, and second demand cannot be met because oxygen intake in insufficient.

In the modern aquarium there are some devices that assist with oxygen such as the protein skimmer. Reliance should never be placed on these devices for the purpose of oxygen supply. If they fail there could be trouble. The seawater in the sump, if one is used, should not be counted into the system net gallonage when stocking is being considered so that those gallons assist with seawater quality including oxygen.

So consider a fish only system which is fully stocked and has been stocked correctly. If the system design is good there should not be any problem with oxygen as long as everything is running. Fresh oxygen is being taken in at the air/water interfaces all the time as more seawater reaches these surfaces and is then distributed around the system.

What if a circulation powerhead breaks down? The seawater movement is clearly going to reduce, though there may still be enough oxygen intake - or there may not. In the latter case, there isn’t any adjustment by the fish to economize on oxygen usage, so they will exist on the oxygen that is available. The demand will reduce the oxygen until it has reached critical levels, and the danger of suffocation arises. This of course will be made worse by the demands of the bacteria in the bio-filter. The same applies with a power cut when all circulation ceases. The reduction in the available oxygen could be more rapid and the danger of suffocation would arise more quickly.

It is clear that stocking is an area where great care needs to be taken. In the reef aquarium there is a smaller danger of oxygen problems as seawater quality is protected by having less fish though care still needs to be taken. In a fish only system with its heavier fish load, and not forgetting to consider the higher numbers of oxygen hungry bacteria there will be, the danger of oxygen depletion is higher.

The guidelines for stocking both reef and fish only systems are readily available and should not be exceeded. In addition, for peace of mind and especially in areas where power cuts are known to occur, the aquarist may wish to consider back-up battery operated powerheads, or even a small back-up generator with enough power to drive the aquarium circulation system and heaters.

No aquarist would wish to see the expensively furnished aquarium suffer or even die because of inconsiderate stocking or the event of power loss. The life in the aquarium deserves better than that.

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Tags: Care, Equipment, marine-aquarium, reef-tank, Water Quality, water-testing

The Local Fish Shop

This will only be my own opinion of course. Then again, I’m always right. Excuse me, what’s that noise - oh, not to worry, it’s only my wife falling about laughing!

The local fish shop is usually referred to as the LFS. The size of it depends a great deal on where the aquarist lives, as near a city they are likely to be small ‘supermarkets’ and in less populated areas they could be quite small standard shops. I live in a small coastal town, and the one close to me is very small. If I want to wander around a much bigger establishment the car needs to come out for a trip to the city.

There isn’t much doubt that the big stores hold a lot more live and shelf stock, it stands to reason. There’s far more to ogle at and sometimes, but not always, the prices are cheaper as some larger establishments also sell on the internet. They are likely to be busier and it is possible the staff may not be able to spend as much time with each customer. This applies most at the weekend, so those who have the option to call in at a quieter time usually find things better.

The small store is sometimes a one man band, perhaps with an assistant at the weekend when things are busier. There isn’t the large choice of live and shelf stock, and often the prices are a bit higher than the larger establishments.

Before buying everything over the internet based on price alone a little consideration is needed. There isn’t anything wrong with buying over the internet, nothing at all, provided the supplier is reputable. However, there are little things that matter a lot.

If an aquarist has a LFS, big or small, then the first thing to do is check it over. Without any intention of buying, wander around and observe. Note one or two prices of commonly available equipment and later check them against the cost on the internet. Are they very much more expensive in the LFS? Have a good look at the display aquariums - are they well maintained and clean, with apparently healthy livestock swimming about? Is there a reasonable choice? Can the shop obtain livestock on request, and who supplies it? Often the establishment that supplies the LFS is known and has a reputation for quality (or otherwise). Some shops are keen to sell whatever to whoever I’m sorry to say, but fortunately they are a minority. The best and most suitable equipment in those shops is always the one they happen to have in stock, even if it isn’t. Quality advice is in very short supply and there isn’t any interest in having a chat. I’ve met the odd shop assistant who hasn’t a clue.

On the other hand there are those LFS’s that, within reason (they’re not rushed on Saturday afternoon) are willing to chat. They will answer questions if they can, and won’t blag on if they don’t know. They’ll be interested in the aquarium the aquarist has, and what’s in it. If the aquarist’s LFS is one of these, then the aquarist’s luck is in.

If the LFS is a big one, then the equipment choice could be extensive and also the livestock. Prices could be very competitive. Becoming a regular customer is well worth while and it is likely the aquarist will become known as a regular - eventually a cup of coffee could appear and a chat in general become usual.

If the LFS is small, then of course equipment and livestock choices will be less extensive. Nevertheless, it is worthwhile purchasing as much as possible within reason. If the shop is a ‘one man band’ then the aquarist will become known more personally to the shopkeeper and that cup of coffee will be a regular occurrence when at the same time the world is put to rights. There could even be a conversation about marine matters! Small establishments are usually well aware that their prices for major items are not particularly competitive, and they accept this. This is so because they cannot bulk buy as the larger establishments can. They sell in quantity items such as additives, dry sea salt mixes, food etc, as well as livestock that usually can be ordered.

If the aquarist is known to the LFS there is another advantage that could be useful. It may or may not apply, it depends how well known to the LFS the aquarist is. If something is to go wrong with aquarium equipment it could happen on a day when everything is closed. Maybe this doesn’t matter, but what if it was the heater? A phone call to the LFS proprietor and hey, no problem.

I recall my LFS proprietor saying that he would be willing to nip and get some piece of needed equipment provided it wasn’t 2am in the morning. He also said he would be willing to repair equipment if necessary and possible but again only for known customers. This applied even to equipment obtained over the internet, if not under guarantee. He would not, however, do it for someone who didn’t visit the shop regularly and buy smaller items as needed. Fair enough I say.

The cost of marine equipment can be quite high, and it is very reasonable to search for a good price and then order it over the internet if the LFS is too expensive. As said most small LFS proprietors understand this. If the aquarist is lucky and has a knowledgeable and helpful LFS then regularly calling in for just a chat (and hopefully a coffee) and purchasing those smaller items as required is well worthwhile.

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Tags: aquarium, home-aquarium, local-fish-shop, marine-aquarium, reef-tank, saltwater-aquarium

The Sulphur Denitrator

There are many ways that aquarists can maintain high quality seawater. Yes, we’re back to that again, but no apologies as it would be great if all aquariums were successful and high quality seawater is very important, in fact, the most important aspect for success.

A problem that regularly makes an appearance is nitrate. Nitrate is a product of the nitrogen cycle, where the bacteria convert the toxin ammonia to the toxin nitrite, which is then converted to the generally non-toxic nitrate. In the full cycle nitrate is converted to gas which can escape from the aquarium.

If live rock is in use then the full cycle should be present, provided there is sufficient live rock and it is of good enough quality. Live rock can be overloaded of course by overfeeding and overstocking, and also by having insufficient quality rock present in the first place. So balance is required - enough food for the livestock, not too heavy a bio-load (too much livestock), enough live rock (enabling there to be sufficient bacterial activity), and regular routine seawater changes of a sufficient amount. Each aquarium is different, and the aquarist should know his or her aquarium’s requirements. It is not unknown for nitrate to be a problem even with all the requirements as shown present, and the cause not discovered.

If bio-filtration is completed by a canister filter, or a fluidized sand filter, or other designs of a similar nature, then the nitrogen cycle only goes as far as the production of nitrate. It follows that as time passes there will be an increasing amount of nitrate present in the seawater. (Infrequently nitrate is not a problem with these filters - there are possible reasons for this that will not be gone into here.) The first action to control the nitrate level is regular routine partial seawater changes. This on its own is often sufficient. Feeding and livestock levels need to be correct as in the previous paragraph.

If nitrate is a persistent problem and the aquarist has failed in attempts to find the cause, and is satisfied that husbandry disciplines are fine, (feeding, the amount of livestock, and the amount of seawater changed at routine changes) then there is another way. It has to be emphasized that this is a way to be tried after all remedial efforts have failed; it is not a first resort. More advanced aquarists will usually wish to try caulerpa in the sump etc in an effort to ‘mop up’ nitrates.

The sulphur denitrator is, as the name implies, a filter that removes nitrate. It is normally in the form of an acrylic tube, 3″ or so in diameter, with a feed at the bottom and an outlet at the top. Seawater is pumped through the tube where the nitrate is attacked. Bacteria again are the workforce. The term used is ’autotrophic denitration’ as I understand it (ref: C. Soler. mars/reefkeepers.net).

The bacteria that convert ammonia and nitrite need oxygen and cannot operate without it. However, the bacteria that convert nitrate are kept in a very low to zero oxygen content environment. If oxygen were to be present the bacteria would use that and ignore the nitrate. However, if oxygen is insufficient the bacteria will extract it from the nitrate, thus breaking the nitrate down. Therefore in the denitrator oxygen is kept at an insufficient level forcing the bacteria to obtain their needs from the nitrate.

The seawater being pumped through the denitrator flows very slowly. In fact, the flow rate can be seen at the return end as a fast drip (when the denitrator is mature). Therefore the pump power need only be low. Often, aquarists divert some flow from the return of a canister filter or similar. If pumped direct from the aquarium or sump there needs to be a mechanical filter before the seawater enters the denitrator.

In the denitrator being discussed the media is sulphur. This is usually in the form of small beads, about ¼” or so. The bacteria live on this media and as they convert the nitrate they produce sulphate on a 1:1 ratio. The bacteria use the sulphur as an energy source rather than have a separate food supply as is required in other style denitrators (heterotrofic types) where additional feeding is required. Sulphate is not a problem to the seawater quality as sulphate is present naturally at a high level, about 2700 ppm (parts per million).

The seawater leaving the denitrator is acidified to a degree. Though it is unlikely to adversely affect properly buffered seawater, it is best to increase the pH. This can be done quite easily and at the same time obtain an advantage. The returning seawater, which is flowing very slowly as said, can be routed through a container with calcareous material in it. The acidified seawater will tend to dissolve this material increasing the pH, and at the same time calcium will go into the aquarium. The calcium flow cannot be relied upon, and tests if necessary still need to be made. It is very unlikely that the calcium needs of a hard coral (SPS) system would be met, for example.

Using a sulphur denitrator could and more than probably would be the answer to a difficult nitrate problem that the aquarist has not been able to resolve in other ways. It is easy to start up and quick to mature, and does not need any additional fiddly feeding as does the other type. It also tends to be more forgiving with flow rate than the other type, but within close boundaries. The sulphur also lasts a long time.

http://mars.reefkeepers.net/USHomePage/USArticles/Soler/DenitratorSoufre.html

http://mars.reefkeepers.net/USHomePage/USArticles/SulphurDenitrator.htm

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Tags: Aquarium Maintenance, Care, Equipment, nitrate, Water Quality

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