Beautiful Encrusting Algae But There’s A Small Downside

Marine aquarists try very hard to create a beautiful aquarium – whether the system is fish only or reef that is the target. These attempts are generally successful and often the picture is enhanced by Mother Nature. Mother Nature obviously provides the ‘eye targets’, the colourful fish and corals.

In the aquarium are usually rocks – whether fish only or reef this could be to provide homes and also be decorative. Both, particularly reef, could be ‘living rock’ for biological filtration. This rock is normally interesting in shape and over time provides a base for algae growth.

At this point the assumption is that the aquarist has properly maintained seawater quality which in turn means that stocking levels are acceptable. It’s also assumed that lighting is adequate.

Encrusting algae, often known as coralline algae which is more accurate, is lovely. It can cover upper surfaces of rocks and make a real contribution to the overall aquarium picture. Often it is introduced to the aquarium on live rock from the dealer or another aquarist. Helpfully, ordinary maintenance seems to assist in its spread.

I’ve taken some photos from areas in my aquarium (I’m not an expert on photography so hopefully they’re adequate!). The heading photo has nothing to do with the subject, it’s just that my flame angel (Centropyge loriculus) cruised by and I couldn’t resist pressing the button.

The next two photos show interesting formations created by the algae as it grows. As is often the case there is beauty in the detail. There is much more in the aquarium that isn’t shown.

Ok, so what’s this downside that has been mentioned? There’s always a price to be paid for anything, and the price demanded for this algae is in an extension of maintenance. However, this isn’t much.

The algae not only uses rocks as a base, it’s quite happy to use glass. On the rear glass this doesn’t matter, and in my case the left hand glass can be left as well. However, the other viewing glasses need to be cleaned periodically. Of course this is already done to deal with the green stuff that accumulates but unfortunately a magnet cleaner doesn’t usually remove the encrusting algae. Therefore a razor cleaner is the best tool.

The next two photos show growth on a corner and on a horizontal glass pump support. Coralline algae seems to like growing in the corners of the aquarium – or at least it does in mine. Cleaning is not a problem with a razor but make sure the razor is sharp and also have regard to the silicone joints if there are any.

Calcium testing is normally carried out where there is a known need for it. There is another test that is generally beneficial particularly with a reef and that is alkalinity. I maintain my alkalinity at about 4.0 meq/l (it drops off slowly, I test at routine seawater changes) and this seems to benefit the encrusting algae – not only the coralline but other types present as well. Maintaining a higher alkalinity is considered to be desirable with a reef system but is not essential.

It has been mentioned that routine maintenance could assist with the spread of coralline algae. When the algae is being scraped off the glass it disperses into the seawater and this seems to generate further growth in other areas of the aquarium, though I have never seen any scientific or other confirmation of this.

One more concern has been raised in the past – does the coralline algae presence on live rock reduce the effectiveness of live rock filtration. Bacteria essential to the well-being of the livestock dwell within the rock so could seawater fail to reach the bacteria causing their demise followed by serious problems? ‘No’ has to be the answer. Though, as far as I know, there hasn’t been serious or scientific testing of this question there hasn’t been a reported failure of filtration, again as far as I know. There are marine aquarists far and wide who are delighted with the presence of the algae. Personally I’m also delighted and have never had a problem with filtration because of the algae presence.

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Making Live Rock

The major bio-filtration media in use by marine aquarists, whether they keep a reef or fish only system, is probably live rock and for good reason.

Premium live rock is rock that has been fairly recently harvested from around the reefs, meaning it is ‘rubble’ rather than hewed from the reef itself. This rock has growths of all sorts which could be of interest to the aquarist. Unfortunately, live rock needs to be cured after import which simply means that all the dead and dying organisms on and in the rock have to be removed, meaning that pollution will not occur in the aquarium. However, for the most part there are tougher organisms that do survive and they could make an appearance in the aquarium, this appearance could be months after the rock has been introduced. Live rock can also harbor unwelcome organisms, such as the aquarium weed aiptasia, an anemone that could become a real nuisance without controlling attention.

In addition to natural organism introductions with the rock, it is very decorative. Reef and fish only aquarists are able to construct a very interesting and decorative structure which suits livestock very well.

The next great attribute of live rock is mentioned in the first paragraph – bio-filtration. Living organisms in the aquarium will literally be poisoned unless there is some means of negating the toxic substances that they produce. The two major toxins are ammonia and nitrite, and a much less dangerous one is nitrate. Dwelling on and in the live rock are oxygen requiring bacteria which convert the toxin ammonia to the toxin nitrite, which is then converted to nitrate. Bacteria living within the rock also require oxygen but find it hard to obtain, therefore they extract it from the nitrate which breaks the nitrate down releasing the residue from the aquarium as gas. The process from ammonia to gas release is known as the nitrogen cycle.

Live rock is a great commodity for the aquarist, providing the major and essential job of bio-filtration and also doubling up as decoration. The rock must of course be present in sufficient quantity to deal with the bio-load present, which is created mainly by fish.

There’s only one problem and that is cost, it’s expensive, particularly the premium grade. It’s expensive to air freight rock. This cost could be controlled up to a point by using base rock as the lower part of the rock structure and premium grade for the surface – but it is still expensive.

One way of avoiding this cost is to create live rock, which isn’t difficult. What is required is inert porous rock, that is, rock that is known to be free of any substance that could be harmful in seawater and also porous. This type of rock is often available in local fish shops and at a very much lower cost than the live variety. It isn’t any use purchasing solid non-porous rock. The second requirement is that there needs to be as much rock as would be used if the live variety were bought, which should ensure that the amount of bio-filtration media will be adequate.

If necessary the rock is thoroughly rinsed before it is placed in the aquarium to form a structure as required. The aquarium is then filled with seawater (note the net gallonage for future use) at the required specific gravity (SG) and heated to the design temperature. Seawater circulation should also be turned on. At this stage there isn’t any need for lighting. The seawater should be left to settle down to the required parameters. Check the seawater SG once it has heated up as temperature could affect it.

Once the seawater is at the required SG and temperature attention can be given to processing the rock. Anyone who has ever used a canister filter for bio-filtration will be aware of the process. A commercial maturation fluid is obtained and added to the seawater at the amounts given in the instructions. Test kits for ammonia and nitrite are also required, and the seawater should be tested in accordance with the instructions. Eventually the ammonia reading will disappear, followed by the nitrite reading. Once the aquarist is sure the reading remains at zero for both, the rock can be considered to be initially mature, that is, there is an initial population of bacteria to deal with toxins.

A test should now be done for nitrate; a level will probably be clearly seen. This nitrate should be reduced by a seawater change until it is as low as possible or preferably undetectable.

Slow stocking can now commence, turning the lighting system on of course. It is important that ammonia and nitrite tests continue, if there is any indication of either ammonia or nitrite stocking should cease until the reading(s) are zero again and remain so. The bacteria need to adapt to the increasing bio-load and must be allowed the time to do so.

Eventually of course the aquarium will be stocked as required. The bacteria population is able to stabilize and after a further say three months can be considered as fully mature. Routine seawater changes, as with any system, need to continue as does testing.

Wait a minute though; we’re supposed to be creating live rock which should be able within reason to deal with nitrate. So it will, in time. It takes longer for the nitrate reducing bacteria population to establish, and once it has the nitrate should be controlled. Relative to live rock and nitrate what does ‘within reason’ mean? It simply means that if the aquarium is often overfed and the toxin reducing bacteria produce a lot of nitrate, and the aquarist is missing routine seawater changes, the nitrate could be too high for the bacteria to control.

Ok, so now we have an aquarium filtered by live rock. What about the natural growths that could occur (though not always) with natural live rock? These will obviously be absent as the rock was initially dead. With both the fish only and reef system, if the environment is of high quality it shouldn’t be long before encrusting algae’s make an appearance. In a fish only system it could be necessary to seed with a small piece of rock from a friend’s aquarium that already has encrusting algae on it. In a reef system, when the aquarist introduces corals they will usually be attached to pieces of natural rock. These rocks should contain organisms that should seed the other rocks provided a high quality environment is maintained. Before long the previously dead rocks should look completely different – just like natural live rock.

So for a considerably reduced price live rock is achievable. What the aquarist needs to provide is some patience (required by all marine aquarists) and considerably less money. There is great concern about the future of the wild reefs and concern has been expressed about the impact of live rock collection, so the aquarist who produces his/her own will be assisting with reef protection.

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How Did I Know The Rock Had Become Live?

All marine aquarists are aware of live rock. It’s the stuff that perhaps the majority use for bio- filtration and it’s also excellent as décor, be it a reef or a fish only system.

Good mature live rock has the usual bacteria present, those that convert the toxins ammonia and nitrite to the much safer nitrate. Unlike a canister filter where the nitrogen cycle stops after the production of nitrate, live rock within reason will deal with nitrate. This is because the bacteria that dwell deep inside the rock would also prefer to use oxygen directly, but because it is in very short supply they remove oxygen from nitrate which breaks it down.

When I set up my current soft coral reef system I used two canister filters for the bio-filtration. (The photo shows the reef in part. You can tell I took the photo!) The bio- media was Eheim sintered glass. It worked very well. Being aware that nitrate could become excessive I built a denitrator based on suphur and this ran from when nitrate was noted as being present even though the reading was very low. Better to defeat a potential problem than wait to tackle a real one. Once the denitrator was matured the nitrate disappeared and I never had any readings at all. This was over the first 5½ years of the aquarium’s life. It has to be said that the fish load is very low; there are two small fish (a blue damsel and a flame angel) in 43 gallons net of seawater.

The reef is built of what is named ‘grotto rock’. This doesn’t come from any grotto so why the name I don’t know, however it’s ideal for marine use as it is totally inert and full of crevices and holes. Just as important, it’s very porous. The rock comes in all sorts of shapes and sizes and it was great fun creating the reef.

The reef developed over the years and I noted the lack of nitrates. I thought I’d do a little experiment at one point to prove the effectiveness of the denitrator; this experiment consisted of turning if off. Difficult!

I monitored the nitrate level and found that all readings were zero (I suppose I ought to state that nitrate was undetectable with the test kit). I left the denitrator off for a week, two weeks, which turned into months. Still nitrate didn’t appear. The canister filters continued to run so nitrate would be produced.

I like looking at the reef from various points in addition to the front and sides. This often involves lying on the floor and peering into the aquarium. This sometimes occurs at night when most of the little beasties are about. The rocks I thought looked more like live rock than the real stuff, with all the worm growths, algae etc. I then wondered if it was in fact live. This thought was supported by the lack of nitrate, the canisters were producing it and perhaps bacteria were removing it? I realized that I did routine seawater changes and this would tend to reduce nitrate levels as well.

The rocks were now live, why not? It was an excellent home for bacteria after all. However, at the end of the day a rock looks like a rock, there’s no way a bacteria presence can be checked. It is a known fact that bacteria exist on surfaces within the aquarium in addition to any intended bio-filtration area, but would there be sufficient to support the aquarium completely? Surely the canister filters would be taking the majority of the bio-load?

I have two canister filters running as said, so it was easy to check. At the next scheduled clean of one of the canisters I removed the bio-media and ran the canister empty (seawater is returned to the surface for oxygenation and to agitate the surface). A careful watch was kept and there weren’t any unwanted effects.

So far so good, but the next stage was a little more cautious. Even though the bio-media from the first canister had gone, maybe the second canister was handling everything, so with the second canister, when the time was chosen to remove some bio-filtration media I only removed half of that present. Hopefully that left would prevent any major disaster from occurring. The amount left was one quarter of the total original amount. This was left for a month with everything being carefully watched. No problems.

Now came the crunch – remove the final bio-media. This was done and both canisters now ran empty. Feeding and maintenance continued as though nothing had changed. Nothing untoward happened.

The system continues to run normally and it is now approaching its 7th year. The inert rock is now live.

To be honest I wasn’t really surprised, though it was very sound to use caution. One way of producing live rock is to mix inert rock in with live; the higher the live proportion the quicker the inert variety converts (it still takes quite some time). There wasn’t any live rock in the system at all at the start; it was all inert, so how did it convert?

The first possibility is that ‘overspill’ from the canisters occurred though perhaps this is unlikely, I don’t know. The second is that bacteria developed on and in the rocks naturally and these expanded in number.

To my mind the most likely explanation is that the bacteria were introduced, though some could have appeared naturally as suggested above. Most of the corals that were introduced are attached to rocks and of course they were attached to these when collected – these rocks are live. So the inert rocks were colonized by the bacteria from the live coral rocks.

When the bio-media was slowly removed from the canisters the bacteria on and in the rocks would have expanded to deal with the increased load and, hey presto, the system is now based on live rock.

The denitrator sulphur media has been cleaned and is not in use. I haven’t actually removed the unit as it isn’t in the way. The good thing is there isn’t any more need for it to be maintained though the maintenance wasn’t a problem. The worst part was the flow, denitrators have a very slow flow and this was occasionally problematical and a bit of a headache. No more of that though.

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It Takes Time

Any experienced aquarist can understand why a newcomer to the hobby really wants to see some livestock in their aquarium, because those aquarists have been through the same process.

Doing things properly is a patience tester. This isn’t a bad thing because patience is at or very near top of the list of attributes that are very advantageous to a marine aquarist. It starts from the word go. First there is the question of the aquarium size and position and also perhaps a bit of diplomacy with the other half. Then there is the question of equipment and its cost, perhaps when the equipment list was complete and also running costs checked, mainly electricity, the aquarium needed to be downsized a little (in itself highly commendable if cost is a question, better to find out early). Collecting the equipment could have taken a considerable period, relieved from time to time by the excitement of opening another box.

Then the aquarium and equipment are all together. Great, off then!  Oh no, there it goes again, slow down, use patience. This is at the stage of livestock of course. The aquarist is well aware of what system it will be, usually fish only or mixed reef (there are some coral only systems about). Having done the research the reason for slowness in stocking becomes clear: the bio-filter. This is the life support for all the life within the aquarium. Without this support it wouldn’t be long before trouble struck, probably with tragic consequences.

The aquarist could be using live rock which is supplied ready for use, or cured (it can be supplied uncured leaving preparation to the aquarist, but the normal is cured). This live rock contains the bacteria necessary for dealing with toxins, namely ammonia and nitrite. These two toxins are deadly and the only acceptable level is ‘undetectable’ or zero. (Live rock should also be able to deal with nitrate within reason, but nitrate is not a toxin in the sense that ammonia and nitrite is.)

Or perhaps the aquarist has chosen a canister filter(s) to provide the bio service. This is fine, though it needs to be remembered that nitrate will be produced by this system and not removed. There aren’t any bacteria present in the canister filter at the beginning, they need to be kick-started. This can be achieved in several ways, though the best is using commercial maturation fluid and following directions.

So the stage is set. Whether it is a ‘matured’ canister filter or live rock, the aquarium should not be fully stocked.

In the case of the canister filter the maturation is primary. There is a bacterial presence to deal with ammonia and nitrite but the bacteria are new and probably few in number. It takes time for them to build and adjust to the full aquarium load. Placing a full aquarium load (or bio-load) would overpower the abilities of the bacteria to cope and disaster would follow. The bacteria would increase because of the high presence of toxins but not fast enough.

What of live rock? This is purchased hopefully with bacteria present. It is fairly certain that bacteria will be present but are there enough to deal with the full bio-load? It must be said that there could be, if the live rock has just been cured and is new for sale. Even then it isn’t certain though. Also, what if the live rock had been in the ‘for sale’ tank for a considerable period, as much of it is? All life needs food and this includes bacteria. If the rock has simply been sitting in a tank then the bacterial count could drop and be quite low.

So we’re back to the beginning, with the words patience and slow. With both live rock and canister filtration, stocking particularly with fish should be slow. This enables the bacteria that are present to have a chance of dealing with toxins which of course is good for the fish and the aquarist. Failure at such an early stage is not pleasant. As time progresses and the bio-load increases the bacteria populations also increase to keep pace and have a good chance of achieving this if stocking is slow. Eventually full stocking is reached and the bacteria then settle down to handling a more or less level load. Once this stage is reached and about three months have elapsed then the bio-filtration can be considered to be stable.

During the stocking period regular testing is required to ensure the bio-filtration is coping. This is easily achieved as ammonia and nitrite tests will hopefully show zero for both. If any reading does appear further stocking should cease and close control on feeding is needed. The readings should disappear and after a week or so of zero readings cautious further stocking can proceed.

During the stocking period routine seawater changes should be completed, these changes continue for the life of the aquarium. The guideline amount to change is 10% of the net seawater gallonage per week. This amount could be flexed once the aquarist has some experience and knows the traits of the aquarium, such as nitrate increase if any.

So what does the word ‘slow’ generally mean in relation to stocking? There are varying opinions though quite often the advice is to ‘stock slowly’ and nothing else, which isn’t particularly helpful.

Corals present a quite low bio-load in the aquarium and it is considered general good practice initially to sparsely populate the reef with the desired corals, which means they are spaced well apart. Later when it is apparent there is space available more could be added. It also gives time for the aquarist to see the extent of expansion that many corals exhibit. Those that do expand, and also those that don’t, grow. Corals of differing types should not touch. A reef that looks overcrowded probably is.

Fish present the biggest load for the bio-filtration to process. When a fish is introduced, feeding also needs to start, so the work of the bio-filtration really begins. The aquarist should have done research on the fish and know their habits and potential final size. It is good practice to put more timid or peaceable fish in earlier than robust and/or more aggressive types.

It cannot really be stated that an additional fish could be placed in the aquarium after every X period. The size of the fish needs to be considered. If a small fish is placed in the aquarium, then of course the bio-load will increase. After a period (see below), if all is well with seawater tests, then a further fish could be added. This also has the advantage that if the initial fish is timid then it has time to settle and become confident in its new home. The next fish could well be a small one too, so the same applies. A further fish could well be larger so it is good practice to increase the time allowed before any further addition, as the larger the fish the bigger the load it places on the bio-filtration. If the fish is an inch larger, allow an extra week. Proceed in this way keeping a close eye on seawater conditions and feeding carefully (meaning minimize excess) and all should be well.

There is a guideline for time periods between fish additions. This is general and not intended to be rigid in any way, particularly if an aquarist is not sure if all is well. In that case, wait! The general guideline is ‘a week an inch’. So if that is followed a two inch fish would require two weeks before another fish is introduced. If the next fish has a length of three inches then a three week period is required, and so on. The fish length excludes the tail. I’m not aware of any scientific evidence supporting this guideline, but it is sensible and works.

If the marine system has been well thought out, once the seawater has been placed into it and livestock is introduced it is the birth of a new mini aquatic world. Everything should be in balance as far as possible. The lighting should suit the corals, the corals should be properly spaced with sufficient seawater movement and the fish should be mutually compatible and suited to the system design, be that fish only or reef. Supporting the aquarium life is the bio-filtration which is absolutely essential.

The foundation for future success is current practice. Give Mother Nature’s bacteria time and they’ll do the job.

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I Did It On Purpose

This sounds a bit like a confession and in a way it is. I’ve done something that shouldn’t be done and did it knowingly. Fair confession!

Now and again I try to find something out for myself by running an experiment. A scientist would advise that they aren’t experiments at all but amateur fiddling, and I accept that. To qualify as scientific there needs to be a control set up for comparison purposes and various readings taken. All I do is observe for the most part.

I keep a soft coral reef lit by a bank of fluorescent tubes, equally mixed marine white and marine blue.

The last experiment – sorry, fiddling – I did before the current one concerned cover glasses. I don’t habitually use cover glasses nowadays though I used to. They were used as they reduced the amount of evaporation significantly. I noticed in the morning when the lights came on that the cover glasses were heavily condensed underneath, so much so that there were droplets visible all over them. I wondered if this condition would affect the light input into the aquarium and therefore the corals. It took a fair while each morning for the lighting heat (fluorescents) to clear the condensation.

So I took the cover glasses off and noted the date. The cover glasses were left off for a full six months and I watched the corals with care, wondering if growth rates or colour would change.

During the six month period the aquarium was treated as normal, there wasn’t any change in the feeding regime or maintenance schedule. I had to increase the top-up amounts as evaporation increased, but this was expected.

I have to admit to some disappointment as I had assumed that the corals would respond to the increase in light. The light input to the seawater would be affected to some extent by the presence of glass covers even though they were kept clean, and the period each morning when heavy condensation was on the glasses also no longer had any impact on the light. However, the corals showed no change whatsoever, either in growth rates or colour. The growth rates and colour had always been good with the cover glasses on, but, as said, removing them had no effect (accept for the evaporation rate).

The cover glasses have never been replaced as I assume the gas exchange should be better at the seawater surface. Hmm, I wonder. Maybe I could check that someday, though there isn’t any real necessity as the fish are clearly healthy with a normal gill beat.

My latest fiddling has been to do with feeding. I always feed carefully as this is where the phosphate comes from, and a lot of the nitrate is generated. Both are undesirables not least because they are fertilizer for nuisance algae. I haven’t any nuisance algae and never have had.

I have a very low fish load consisting of one Flame Angel (Centropyge loriculus) and one blue damsel (Chrysiptera cyanea). This represents a very low bio-load on an aquarium that has been running for 6½ years (i.e. the aquarium is aged and fully mature). I was interested to see if the bio-filtration, all those hardworking bacteria, could cope with a sudden increase in load.

I used to use canister filters for bio-filtration but fairly recently have removed the media as the rocks are live (when the aquarium started they were dead and inert). The period between that action and now means that any bio-filtration has transferred to the rocks. After the canister filter media was removed there wasn’t a problem of any sort and nitrate didn’t appear (there isn’t a nitrate reducing device on the aquarium nor any Caulerpa algae etc). This shows that the bacteria on and within the rocks cope.

I didn’t want to upset the balance of the aquarium by introducing any new fish, I’m very happy with the set-up which has been very successful. How could I increase the bio-load?

I decided to overfeed. Yes, that’s right, doing that which we say over and over shouldn’t be done! As said previously, I feed very carefully and am fully aware of the fish’s appetites and what is enough. They are fed a basic of marine flake and varying frozen foods, mainly enriched brine and mysis shrimp.

I carried out my normal Sunday maintenance and that evening, when a normal feed was due, I fed the usual amount. At the point when I normally cease to feed, I continued even though the fish weren’t interested. About ½ of the normal amount was fed additionally. This overfeeding continued for a full week and ceased on the following Sunday evening when a feed was due, this feed reverted to normal.

During the overfeeding period I watched the aquarium more carefully than usual, particularly the fish in case there was any sign of discomfort. An indication like this could have signaled the appearance of ammonia and nitrite. There weren’t any negative indications whatsoever.

Mid-week I did an ammonia and nitrite test just to be sure, there wasn’t anything detected. At the end of the week I did a nitrate and phosphate test, again nothing was detected. (It should be pointed out that I continuously run an anti-phosphate filter.)

It is now about 3 weeks since the testing began and nothing has appeared that shouldn’t be there.

Only one indication of the additional feeding appeared, and this was heavier than normal algae on the aquarium viewing glasses. This was not heavy, but there was more. This was easily cleaned off during maintenance.

So I have to assume that the bio-filtration is quite capable of holding its own, though the percentage increase in the bio-load because of the food is…I haven’t a clue! The amount of food put into the aquarium (flake and frozen) was 50% higher than usual. The Baensch Marine Atlas advises that, assuming a protein content of 50%, one gram (about a teaspoonful) of flake can add 336 parts per million nitrates, this is after the nitrogen cycle process completes of course.

It could be commented that there wasn’t an effect as the fish load is so low. Is this correct though? The size of the bacteria populations will be dependent on the demand made upon them.

I was surprised that there wasn’t any effect apart from some glass algae though. I thought bio filtration couldn’t adapt that quickly.

Then I had a further thought. My aquarium, particularly at night, displays a large population of tiny life forms. Any food available that has not been touched by the fish could well have been eaten by them. Nevertheless, the food has gone into the aquarium and the process of consumption would lead to waste. So again the bio-filtration must have coped. It also demonstrated that live rock can complete the full nitrogen cycle, from ammonia to nitrogen gas, thus the lack of nitrate.

As already said, this wouldn’t qualify as a definitive scientific experiment. I found it interesting though, and at the least it gave me confidence in the live rock ability now that the canister filter media is no longer there.

Now, may I point out that my aquarium is very mature and also that I can claim experience. Overfeeding is a definite no-no and should be avoided. Seawater quality is the number one priority and overfeeding will not help at all! I only did it for a week and reverted to careful feeding afterwards.

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The Move to Natural Methods

Many modern marine aquariums use ‘natural’ methods as much as possible. This has been achieved by the advances in knowledge that have been made over the last few years.

Some aquarists argue that it is impossible to keep an aquarium without using natural methods and I can see where they are coming from. The point they have in mind is bio-filtration, all those hard working bacteria getting rid of the toxins in the seawater. Without them we’d be in a sorry state. It’s true as well that this filtration is natural. However, if the bacteria colonies are housed in a canister filter then it isn’t completely natural, the home for the bacteria is being provided by our technology. Nothing wrong with that as it stands.

A fully natural method for bio-filtration, staying with the example, is live rock. This rock mainly comes from the wild and has bacteria present. It is a really good filtration media and, unlike the canister filter, within reason the bacteria can deal with nitrate as well. Can’t be bad!

There are new commodities on the market that are designed to replace live rock. This is a rock that appears very similar to the fully natural variety but needs the bacteria colonies kick starting in the same way a canister filter does. One running the new rocks are suitable homes for all bacteria including those that deal with nitrate. This isn’t removing ‘natural’ filtration; the difference is purely the type of rock. There isn’t any electric motor required. It also reduces the demand from the wild, unless the live rock is aquacultured in the wild.

Anyway, getting back on track, there are a few ways that an aquarist could use natural methods. Think of filtration by algae, deep sand beds, plenums, mangroves etc.

The link below is to a website article where natural methods are definitely in mind.

http://www.practicalfishkeeping.co.uk/pfk/pages/show_article.php?article_id=551

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Should You Go ‘Sumpless’ Or Not?

Many aquarists have a sump attached to their display aquarium. The numbers that have a sump seems to advise that the answer to the title question is ‘Don’t go without a sump’.

In fact there isn’t a requirement to have a sump. There are a good number of marine systems that do not have one and they are successful. This applies to both fish only and reef aquariums. There are articles on aquaristsonline.com that suggest a basic kit list and a sump is not included. So why then do so many aquarists use them?

A sump is another seawater container that is often placed beneath the display aquarium though it could be elsewhere provided that gravity is available to feed seawater to it. The sump is more often than not another and usually smaller aquarium. Normally an overflow in the display aquarium is connected to pipe work that carries the seawater down, and the seawater is lifted back up to the aquarium by a pump. The guideline for the speed seawater moves through the sump is the system net gallonage times three.

The size of a sump is simple to calculate, it should be as large as is practical. The larger it is means that it will contain more gallons and that is the first advantage. With a sump the gallonage of the system is increased, which is good for seawater quality. The gallons held in the sump should not be used in any stocking calculation as this would negate the quality aspect of the extra gallonage and, with fish, there is the danger that the physical area of the display aquarium would be overloaded resulting in disputes and aggression.

Heaters and a protein skimmer intake are not exactly natural looking in the display aquarium, though many aquarists manage to reasonably hide them. If a sump is available the heaters can be placed in there and a skimmer can stand alongside, in or hang on. This removes the ‘eyesores’ from the display area and probably makes them more accessible. The protein skimmer in particular needs to be easily accessible for regular maintenance.

The usefulness of a sump doesn’t stop there. Seawater filtration is very important and the move nowadays is towards natural methods. Live rock is a good example. Using a deep sand bed (DSB) or plenum (a raised sand bed) is a good partner for live rock offering good additional filtration, and the best place to locate such a sand bed is in the sump. The guideline for the area of a DSB is 2/3rds of the display aquarium base area. This isn’t always achievable so the largest sump that will fit is again an advantage. The DSB is deep, hence the name, but this doesn’t stop the heaters and protein skimmer intake from going in the sump as well.

Still on the filtration theme, some aquarists grow the macro algae Caulerpa in the sump, which is designed as an aid to filtration and seawater quality. The Caulerpa will help remove, among other things, nitrate and phosphate. These two are implicated in the growth of nuisance algae.

The sump should not be used as a refuge for a sick fish as it forms part of the overall system seawater gallonage. For a fish suffering from excessive harassment it could be a temporary home.  Also, if a life form appears that is unwanted the sump could again be used as a temporary home. A Mantis shrimp for example.

There isn’t a requirement to have a sump immediately the system is set-up, although this is really the better way to go – have the advantages from the start and avoid moving equipment later. A sump could be added later and in this case it is advantageous to consider it at the design stage. Though there are siphon based overflow boxes available, the best way of getting seawater to the sump is into overflows and down pipes. This requires a hole or holes in the display aquarium. These should be drilled before the system is set up. If they are not going to be used straightaway they can be temporarily covered.

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