Enough Light? Must Be

Watching a marine aquarium is a great pleasure and probably one of the major reasons why so many keep them. With a reef system sometimes a new arrival is seen to appear, or a species of coral that is already present appears somewhere else.

On a few occasions I’ve noticed arrivals that must have come in with coral rock, such as a very dark and tiny crab that was very timid and only appeared at ‘dusk’. Its presence was shown by an exploratory claw appearing out of a crevice. The crab hasn’t been seen for a long time and no doubt has gone.

Corals too can appear when new live or coral rock is introduced. In this case the coral type is already present in the aquarium with a fairly large colony, and the new appearance is in a completely separate part of the aquarium.

As far as I can tell, the main colony is a Rhodactis species (the purchase was made years ago and the dealer didn’t have a clue). Rhodactis are also commonly known as hairy mushrooms and mushroom anemones. I think it could possibly be Rhodactis indosinensis – but is this correct as most grow larger than my specimens? Maybe they are Discosoma species. The colony is receiving plenty of light as it is half way up the reef (about half way up the aquarium depth). The new one, however, is not; it is right down at the bottom. The aquarium is 24″ deep (21.5″ from lights to coral). Further, this new growth is at the end of the aquarium and is partly shadowed by another coral.

Is my lighting system powerful? No is the answer, it’s a fluorescent array of five tubes, three marine whites and two marine blues (actinic). They’re not even T5’s, they’re T8’s. The reef is furnished with soft corals and they are perfectly happy but I had to wonder at the growth of this new one. The blues will penetrate well but even so….

The original colony is in an ideal spot apart from seawater flow which is a bit too vigorous, they prefer weak flow. However, I’ve left things as they are as the mushrooms are clearly healthy and open well, though not to as large an extent as with lower seawater flow.

The new one is the reverse; it’s in an area of slow flow. However, as said, I wondered about the light. It has been slowly growing for about 8 months now and has reached a size of 3″ across, which, because of the slow seawater flow, is full expansion. However, though I believed the slow growth must be because of light, or at least the lack of it, it seems this could be wrong. Looking at one of the references available to me * it seems that though light is no doubt an influencing factor it isn’t that important, as strong lighting is not required by Rhodactis species though they will tolerate it. Discosoma species prefer in many cases reduced light.

How did the new growth appear? It is possible it’s by natural detachment, but in this case is more likely to be my error. From time to time I have to get out the trusty and sharp scissors and reduce the colony to prevent interference with other species. Part of this is catching the detached parts. These corals are easy to ‘frag’ so if a small part escaped my attention and lodged it is more than likely to grow.

So there we are – what started as a general belief followed up by some simple research has turned my notion upside down. Goes to show how important basic research is. As far as identifying the species, I’d need a marine biologist and I bet there’d be uncertainty even then.

(*Reference: Aquarium Corals. Eric H. Borneman)

---

Breeding Seahorses

Despite the fact that more advanced marine aquarists visit Aquaristsonline in increasing numbers the website was originally targeted at beginners. Nothing has changed, so why is anything being written about breeding which is in the area of the more advanced among us?

The answer is that earlier, and also more recently information has been given about keeping seahorses, such as how to create the necessary species aquarium etc (see blog and ‘Articles’). I have a soft spot for these endearing creatures and at the same time am well aware of the pressure on them in the wild because of collection. Therefore it seems reasonable to ‘round off’ with something about breeding.

In the first place it must be stated that breeding these creatures is not for the complete beginner. Any aquarist who has bred marine fish including the ‘easier’ clowns could proceed. Don’t let that put you off though; it’s not beyond the scope of anyone who has accumulated some experience. How can the level of experience be judged? The aquarist must be absolutely capable of maintaining continuous high quality seawater, and this is easily shown after say a year with the use of test kits. Definitely zero ammonia and nitrite, and a very low level, if any, of nitrate. Phosphate is best undetectable. Finally, any other requirements specific to the type of aquarium system need to be acceptably stable at the correct levels, such as calcium etc. If the aquarist is able to maintain the required parameters as a matter of course then ok, the seawater in the seahorse aquarium will also be maintained at high quality. It is clear that seahorses, as with fish, need to be happy and healthy before there is any chance of breeding, and this depends very much on their environment.

Now I’m not going to start advising the best way to breed seahorses and how to do it, there are those better qualified than me. So what I have done is provide two links:

http://www.petplace.com/fish/how-to-breed-a-seahorse/page1.aspx
http://www.spc.int/coastfish/News/LRF/5/10Breed.htm

Successfully keeping a seahorse aquarium is very satisfying. Actually breeding them must really be wonderful and a source of great pride. In addition, the local fish shop or marine aquarist colleagues would no doubt be interested in the offspring so there won’t be any difficulty in sourcing placements. Finally of course the pressure from collection will be eased that little bit more.

---

Remember The Lighting

What is the most important part of a marine system? Lighting? Well no, it isn’t, seawater quality is the number one with both fish only and reef aquariums.

High seawater quality means there shouldn’t be any indication of ammonia or nitrite. Nitrate should be as low as possible (the guideline for a reef system is less than 10 ppm (parts per million) and for a fish only less than 30 ppm. Phosphate should preferably be undetectable. pH should be stable in the region 8.1 to 8.4. SG (specific gravity) for a fish only should be stable within the range 1.022 to 1.025, and in a reef system 1.024 to 1.025 (there are variations with SG which more advanced aquarists use for specific purposes). With a reef system there are more seawater parameters that could be monitored but those given are the basic ones.

So what has seawater quality got to do with lighting, this text is about lighting according to the title.

There are occasions when an aquarist is completely at a loss to explain why the corals are not as they were, with reduced growth and less expansion. Tests have been carried out on the seawater and it is top notch. What could be the problem? Perhaps a disease that is hard to spot? In fact it could be the lighting. Great care is taken when setting up a reef system to ensure the lighting is suitable and the corals, hard or soft, will confirm this.

With a fish only aquarium the lighting is not of such great importance. Its function is to permit the fish to see and the aquarist to see the fish. In addition, if the lighting, which is usually fluorescent tubes, is chosen with care the fish colours can be enhanced. Some colours react really well to ‘marine white’ tubes, and likewise to blue (actinic) ones. There isn’t any reason why more than two tubes cannot be used, but at least two should be in use, say one ‘marine white’ and one blue (actinic). Doing this not only assists with fish colouration, it permits the aquarist to create a ‘dawn/dusk’ sequence. Using electric timers, the blue tube comes on first, then half an hour later the white. At the end of the day the white goes off followed by the blue. This avoids washing the aquarium with sudden light and plunging it into instant darkness, both bad practices.

The reef aquarium is a different story. With these systems lighting is a close second to seawater quality. Most of the corals commonly kept have zooxanthellae in their flesh. Zooxanthellae are single celled algae and the coral gets its colour from them. In addition the corals obtain food as ‘rent’ from the algae; authorities have quoted the level of food supply as 80% or more. Algae, as other plants, require light in order to photosynthesize. The light needs to have sufficient power to penetrate the seawater to the depth of the corals and reach the algae. Power is measured in watts (W). If power is insufficient then the algae will get too little, this is why different power requirements are quoted for aquariums with different depths. In addition, the spectrum needs to be suitable. Light is measured in Kelvin, otherwise known as the colour temperature. Though there is more than one colour suitable for photosynthesis with some corals, blue is the one commonly used by aquarists. Blue penetrates deeply into the seas and oceans. Generally all light types use the Kelvin scale. If metal halide lighting is in use, the bulb(s) commonly used are 10000K and 14000K. The higher the number, the more cold or blue the light appears. Many aquarists use blue (actinic) fluorescent tubes alongside their metal halides. Many commercially produced metal halide arrays incorporate these tubes.

With reef lighting it is also advantageous to have a ‘dawn/dusk’ sequence. Whether the main white lights are fluorescent or metal halide, having blue tubes allows the sequence to be arranged.

So corals, or rather the zooxanthellae in their flesh, need lights that have a suitable colour and in addition the lights need to have enough power to penetrate the seawater.

Provided the aquarist has chosen the correct lighting system in the first place and other requirements are as they should be, the reef display should be lovely. This continues for longer than a year or more when eventually the aquarist notes that the corals aren’t as they were, as said earlier. There appears to be a slow reduction in extension. Perhaps there is a slight and maybe continuing change in colour. Again as said, the aquarist gets out his/her array of test kits but nothing appears wrong, the seawater is still of high quality. How about the lights?

With a fish only system there doesn’t need to be too much concern about the lights. As said they are normally fluorescent tubes and need changing when there is clear discolouration or blackening at the end of the tubes. It is not long after this point has been reached that the tubes are likely to start flickering or fail.

With a reef system the lighting needs more careful monitoring. To the aquarist’s eye there seems to have been no change to the light, as the tubes and/or bulbs switch on normally and they seem just as bright. This is not so however. As time passes the tubes and/or bulbs start to reduce in power which means that, given time, less light will reach the zooxanthellae. In addition, over time the spectrum shifts slowly and the painstakingly chosen lights emit a changed colour, again something the corals will not appreciate.

The best way that a reef aquarist can proceed is to keep a notebook; it only needs to be a small one. In it can go all sorts of memory joggers – including when the lights were first turned on. The manufacturers usually suggest in their documentation how long the lights should maintain their original specifications. There is considerable discussion within the hobby about light reduction/change periods, some suggesting that lights should be changed every three months. I have no facts or scientific reports to argue with, but I feel that period is definitely safe but rather short. Changing the lights no later than one year seems to be a reasonable general guideline. My reef is lit by a fluorescent array, and I change every nine months and have not had any problems.

The aquarist carries out many maintenance activities, a number of which are quite rightly concerned with seawater. There are the test kits that need to come out of the cupboard regularly, the routine seawater changes that partially replace lost trace elements and dilute the sometimes troublesome nitrate. Then there’s cleaning that very useful device the protein skimmer and ensuring that seawater flow is optimal. Plus the rest.

The lights are just there. They may get an occasional wipe with a damp rag but that’s usually all. They’re very dependable and all that is needed is a bulb/tube change after a specific time lapse. This will keep the corals happy if other parameters are good.

Happy corals mean a happy aquarist.

---

Interesting Maybe, But It Doesn’t Matter

Interesting?

O3        +  NO2 ………> O2         + NO3
(Ozone + Nitrite ………> Oxygen + Nitrate)

Could be, but in the majority of cases the answer is no.

A potential marine aquarist or even an existing one keeping a reef or fish only system is likely to shy away from anything approaching scientific, and fair enough. (The above is straightforward and understandable if the symbols are understood but gives the general idea). Being a marine aquarist doesn’t mean a white laboratory coat is required or a ‘professor’ appearance, though there are one or two aquarists who love to mystify the marine aquarium and elevate their accomplishments. There isn’t any need to boost success with an aquarium; it is there for all to see.

Some books contain explanatory formulas that would cause consternation with any ordinary person. This isn’t to say that scientific formulas are a waste of space, they aren’t. They are of use to a scientist of course, and interesting to those with experience who wish to delve deep. The same principle applies to many hobbies.

The hobby needs science; it is the scientists who explain. The hobbyist doesn’t need to be involved at that level.

Even when avoiding science troubles still arise. The new aquarist, particularly if interested in a reef system, is still faced with gobble-de-gook. There seems to be an unending stream of needs that must be met or failure will occur. Worse, much of this is in shortened version such as KH (for Kelvin), SG (for Specific Gravity), Alk (for alkalinity), temp (for temperature), calc (for calcium), ppm (for parts per million) etc, never mind the variations with lighting; there isn’t a need to go on. Much of this shortened terminology is often used when hobbyists are ‘chatting’ on forums.

Even when the potential aquarist knows what it all means, the problem doesn’t stop. Seawater quality is the number one requirement so the beginner starts to delve into that. The important parameters are discovered but then there are comments on forums and in books about balance – if this is low that will suffer, generating more confusion.

The beginner can flounder at this stage and start to wonder if it’s worth it, it’s supposed to be an enjoyable hobby, at least that is what was understood at the beginning.

The beginner is going to be a successful marine aquarist with some perseverance and if research is done. The research doesn’t need to be into how everything works and what depends on what. The marine hobby has been going for long enough for scientists and advanced hobbyists to have discovered what leads to success. This doesn’t include deep studies into seawater make-up as an example.

It is now well known what ‘high quality’ seawater means. There are tables available that suggest the levels of various items. For example specific gravity is usually quoted as 1.022 to 1.025 for a fish only system, and 1.024 or 1.025 for a reef system. So the aquarist maintains the seawater at the chosen level having considered the given advantages of numbers within the scale. Other parameters are maintained at the levels suggested for them and doing so generally removes the problem of imbalance. It is also known what is not required in the seawater, for example nitrate. Again there are guidelines that suggest upper limits for different systems, so these levels can again be maintained. The beginner aquarist will also have learned of the need for stability and how to achieve this.

So the marine hobby isn’t a scientific challenge for a beginner or anyone else. All that needs to be known are the suggested levels for a marine system, and then maintain them. It should also be said that the system itself needs to be basically adequate, but again these needs are well known and obtainable.

So the mystique is gone. It must be said that patience and a basic understanding are required. The basic understanding is just that, the numbers that represent the levels that livestock require within an adequate system. When this is achieved and maintained, all things being equal success is on the way.

That doesn’t mean to say however that the aquarist never delves into the world of science. Once the ‘bug’ has bitten, some aquarists have to pursue knowledge about ‘why’, and that is to the advantage of us all.

---

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.

---

An Attached Quarantine Tank

Having a quarantine tank is generally accepted as ‘a good thing’. Strangely, the majority of marine aquarists don’t use one, instead throwing caution to the winds or at least relying on good luck. Perhaps they obtain their fish from sources where they are guaranteed to have been successfully quarantined.

Anyway, this isn’t about the merits of quarantine, this is about continuing usefulness.

Quarantine tanks don’t need to be large, just large enough to comfortably hold the largest fish that will occupy them. All the same, it is a little irritating to have an available space doing nothing – the tank sits there empty. The tank can of course be used as a hospital tank should the need arise, but this is hardly ever needed particularly if quarantine has been completed on carefully selected and compatible livestock.

An idea came up recently about a way of using a quarantine tank as part of an overall system so that it wouldn’t sit and ‘do nothing’.

The tank would be selected to ensure it could accommodate anything likely to go in it. It would then be connected into the main system permanently. Err, sorry, what was that again?

Instead of the quarantine tank sitting empty most of the time it would be connected to the main display system as a permanent feature. This gives the advantage that the system would hold more gallons of seawater. It would not be intended to be stocked with anything, just have seawater flowing through it. (Hmm, how long would that last I wonder, aquarists tend to fill empty spaces.)

The tank would be fed seawater that was circulating through the display aquarium and any sump. See the first problem? Of course you can, any problem in the tank would become an available problem throughout the system. Disease for example, the very thing that the quarantine tank is designed to prevent entering the main display.

The idea went on that this problem could be prevented by using a UV (ultraviolet) sterilizer. UV sterilizers (some call them filters) kill or severely damage unwanted organisms as they pass close to the UV light (they do the same to good organisms as well). The seawater exiting the quarantine tank would flow through the sterilizer and therefore anything unwanted would be dealt with. On the face of it this isn’t a bad idea.

The first problem is that the flow rate through the UV unit has to be correct. This is because in order for the UV unit to be effective organisms have to be exposed to the radiation for a long enough period. Therefore the flow rate would probably have to be slowed down.

The second problem is that good as a UV sterilizer is there isn’t a guarantee that all organisms passing though will be killed or sufficiently damaged. Most probably would be or the UV sterilizer wouldn’t exist – but there isn’t as said a surety that all will be properly dealt with. So the system as a whole would be at risk.

The next is not really a problem, more a discipline. The aquarist would need to ensure that the UV bulb, which has a specific life, was renewed well in time or its effectiveness would reduce.

So the basic idea is flawed. However, how about a small modification? How about placing a shut off valve on the outlet from the tank? This would require a complication which is another outlet for the seawater to go through the UV unit. This would be easily achieved by fitting in a correctly rated powerhead to run seawater through the UV unit and back again. Oh, there’d need to be a shut off valve on the inlet to the tank too or it would overflow. Things are getting a bit too complicated. With the shut-off valves at each end of the tank it is now independent of the system.

Many aquarists use a UV unit fulltime or part time or as necessary. Fine, there’s no problem there. Many aquarists don’t use them at all. It’s a choice. But the UV sterilizer is not an answer to the quarantine question.

The only way a permanently attached quarantine tank could work, as far as I can see, is to have stop valves on the seawater input and output. Therefore the tank could not be plumbed directly in line with the display aquarium and sump, it would have to have a direct feed to and from the seawater source which wouldn’t interfere with overall system circulation.

Under normal circumstances (that is, empty without livestock) the quarantine tank would be full of seawater flowing through it, which is an advantage to overall gallonage. If the time came to use it as a dedicated quarantine area, the first action would be to turn off the input and output valves to isolate the tank.

Another problem now arises and that is seawater circulation. Now that the tank is isolated there isn’t any circulation so there would need to be available a low powered powerhead to deal with this. The next problem is that the circulating seawater would cool down, so a small heater would be needed. Then, for the security of the quarantined fish, a suitable clay pot, for example, would be needed as a temporary home.

Light needs to be considered – is there enough light over the quarantine area? Would any need to be added for the comfort of the fish?

Once the quarantine period was over, before the inlet and output valves were opened, all the seawater in the quarantine area would need to be removed. Most could probably be siphoned out. It would be important to dry out the tank entirely particularly if any copper treatment had been used, and probably rinse the area out as well. Not particularly difficult, but another necessity and complication.

All of this leads to the thought that it would be better to stay with the unattached quarantine tank. They are usually small and can be put out of the way somewhere with the powerhead and heater inside.

Having an additional tank attached to the main system isn’t a bad idea, as said it increases gallonage. Also it could house further filtration or even special livestock of interest to the aquarist. There wouldn’t need to be inlet and outlet stop valves either!

There is one thing that must be said and this is that thinking ‘outside the box’ is one of the ways that the hobby progresses, so the aquarist who mused over this idea is to be congratulated – the idea is not practical when examined, but it is an idea.

---

Conversions

Here are a few conversions which could be useful to someone, you never know. The ones shown are those that could be applicable to aquarists, maybe!

To find volume.

Multiply length by breadth by height. (If finding the water space volume of an aquarium it is more accurate to measure from the water level. It must also be remembered that volume will be taken up by rocks and sand.)
Cubic inches to cubic centimeters – multiply by 16.3871
Cubic feet to cubic meters – multiply by 0.0283
Cubic centimeters to cubic inches – multiply by 0.061
Cubic meters to cubic feet  multiply by 35.315

Converting Centigrade to Fahrenheit.

C                         F
24                        75.2
25                        77 (the temperature many aquarists use)
26                        78.8
27                        80.6

Length.

(10 millimeters = 1 centimeter)
(1 inch = 2.5 centimeters)
Inches to millimeters – multiply by 25.4
Feet to meters – multiply by 0.3048
Millimeters to inches – multiply by 0.0394
Meters to feet – multiply by 3.2808

Area.

To find area multiply length by width.
Square inches to square centimeters – multiply by 6.4516
Square feet to square meters – multiply by 0.0929
Square centimeters to square inches – multiply by 0.155
Square meters to square feet – multiply by 10.764

Capacity.

UK fluid ounces to liters – multiply by 0.0284
US fluid ounces to liters – multiply by 0.0296
UK pints to liters – multiply by 0.5682
US pints to liters – multiply by 0.4732
UK gallons to liters – multiply by 4.546
US gallons to liters – multiply by 3.7854
Liters to UK fluid ounces – multiply by 35.1961
Liters to US fluid ounces – multiply by 33.8150
Liters to UK pints – multiply by 1.7598
Liters to US pints – multiply by 2.1134
Liters to UK gallons – multiply by 0.2199
Liters to US gallons – multiply by 0.2642

Weight.

Ounces to grams – multiply by 28.3495
Pounds to kilograms – multiply by 0.4536
Grams to ounces – multiply by 0.0353
Kilograms to pounds – multiply by 2.2046

(Reference: The Chambers Dictionary)

---

Next Page »