By Bob Goemans
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Bob Goemans corresponds with Joe Smith

Joe Smith writes...

Dear Bob

Firstly, I would just like to say that I am finding your Water Quality Guidelines booklet invaluable now that I am fully entrenched in the reef-keeping hobby. My knowledge inches forward each time I return to it (which is often!).

My first query concerns the 'Aragonite Solution' mentioned in the above booklet, which I have been using on a small scale. I have a 5 litre bottle (1.3 US gallon), with about 1 litre (0.26 US gallon) of sugar-fine aragonite sand, to which I add RO water. I was pleased to note the pH of this water changing from about 6.5 to over 8. However, despite rinsing the sand repeatedly before use, every time I add RO water to this bottle, it clouds slightly. So far I have assumed that this is not really a problem, as only a small amount of this water is used for topping up and feeding, and better to be adding a bit of cloudiness, than a weak acid. But what is this cloudiness, and can I continue to use the water as I have been doing, or might it be significantly impacting water quality/clarity each time I add it?

My second query concerns stocking. I aim to make my 240 litre (63 US gallon) system a Caribbean-themed tank. I presently have a chalk bass and a royal gramma, and would like to add more of these two species. I am concerned, however, because the gramma is very feisty. I am aware of the tactic of adding conspecific fish at the same time to diffuse tensions, and this is something I could do, because the two fish are actually residing in the 61 litre (16 US gallon) sump, while the top (180 litre) tank matures separately (long story!). Do you think it would be sensible, once everything is ready, to add another gramma when the two fish I have move upstairs, and then later, two more chalk bass? I would also like to add a small group of blue chromis, but am concerned because I have been told they are difficult to feed. Do you believe this to be the case? The sump will be converted to a mud and chaetomorpha refugium, and I am able to feed my fish three times a day, while the lights are on. What do you think are the chances of success with this species?

Finally, I would love to have a member of the angelfish family in the system, and the obvious Caribbean choice for a tank this size is a cherub angel. But two things concern me with this fish, the first being its reputed pugnacity, and the second being that whenever I have seen a specimen in dealers' tanks, all they do is swim up and down against the glass, trying to get out, which for me is a big no-no - I never keep fish that display this 'pacing' behaviour. Would they continue to do this once settled in a reef tank, or do they adapt well and happily to aquarium life?

If you could shed any light on the above, I would be most appreciative. And lastly - do you have any plans to commit all your knowledge between hard covers? This would be an 'obligate' acquisition for me - so here's hoping that you will!

All the best,

Joe Smith

London, England

Bob replies...

Hi Joe,

Thanks for the nice words about my Water Quality booklet, as it's been very popular!

As for the cloudiness of the aragonite solution when stirred, those fines in solution are simply calcium carbonates that have yet to fully dissolve 100% and/or settle out. It won't hurt anything, but looks quite messy/cloudy. I allow my aragonite solution to settle so the water is clear and then draw off the clear liquid. I suggest having two or more bottles with RO water and sand instead of only one, then using only the water from the bottle with the clearest water. That way, one of those bottles will always have enough time to settle out before the liquid is used.

As for Serranus tortugarum, the Chalk Bass, it does well in small groups and is quite peaceful, so adding one or two additional specimens is not a problem. As for the Royal Gramma, Gramma loreto, it also can be maintained in small groups if given a vertical wall structure with a large overhanging edge or a cave with only one entrance and large enough to hold all the specimens. As for the Cherub Angel, Centropyge argi, that would present a risk, especially in the smaller aquarium, one I don't recommend taking! And as for the Blue Chromis, Chromis cyanea, I have often kept small groups, and yes they have proven to be difficult to keep only because I've found they don't ship well. Yet once I had several healthy specimens and they well acclimated and being fed several times a day, they faired very well and were always peaceful. So the grouping, except for the pygmy angel, is a workable group in my opinion. However, in a 63 gallon system, would limit total number of specimens because of their size to no more than ten.

And yes, you'll want to get a copy of my latest book, 'The Marine Fish Health & Feeding Handbook' published by Microcosm, which is available on various websites where quality books are sold.

Hope this helps,



Stocking Recommendations; Aragonite; Angelfish

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