[harris51]

I could use a more experienced opinion..... I have a 73 bow reef with 2 MH and 4 Actinic bulbs, 90+ lbs of live rock, sump, refugium, Berlin skimmer.... Recently, my clove polyps and a new polyp colony stopped opening as they have always done. I was at a loss for why, as the water parameters seemed unchanged (0,0,0, Trace Nitrates). I had my calcium go into the 700s a few weeks ago after a bad experience with a seachem block. But other than that, nothing unusual. Last night, I found my Maxima clam spawning.... Yes I realize that this could be another sign of stress from something wrong. After my evening of aggressive filtering and watching my protein skimmer go crazy. It occurred to me that maybe there had been a spawn before that I was not around to witness and that might be a cause of the changes in the tank. While I don't have a dissolved O2 monitor, the fish I have appear unaffected, unstressed with no signs of hypoxia. Any suggestions on what I should look for... other than a nitrite spike with the decay of the gamets I missed?

[Ninong]

Originally Posted by harris51

I had my calcium go into the 700s a few weeks ago after a bad experience with a seachem block.

I wouldn't use those if I were you. A sudden change in either calcium or alkalinity can result in a sudden change in pH, which can be detrimental to some inverts. It's hard to say what might have caused your problems but sudden changes have been known to cause trouble. The most common accident is when someone experiences a sudden overdose of Kalkwasser due to a mechanical malfunction of some sort.

Last night, I found my Maxima clam spawning....

Which must have made your fish very happy.

I doubt that a single maxima clam spawning would cause significant problems in a 72-gal tank other that what you observed with your skimmer. I have a 1-hr DVD of a couple dozen large clams spawning simultaneously for more than 20 minutes in Wayne Shang's previous 300-gal tank (he upgraded to a 718-gal tank several years ago) and the thing that struck me the most was how excited the fish were at this unexpected feast. Granted his tank was four times as large as yours but he kept about two dozen clams, including some really large ones, especially one very large gigas. I believe he actually has about three dozen clams in his new tank now.

Here is a brief 1-minute video clip taken several years ago of two maximas spawning simultaneously in Wayne's old 300-gal tank.

[harris51]

Yes, I learned my lesson with seachem blocks.... the water can't be moving at all... or boom. I won't be using them again. I was really surprised about how cloudy the one clam spawning could make the tank. It looked like a large load although it cleared easily with a canister filter... I hope. I have a clam book that talks about rapid oxygen depletion. Yet, your experience is that it is not that big a deal? Thanks

[Ninong]

Originally Posted by harris51

Yes, I learned my lesson with seachem blocks.... the water can't be moving at all... or boom. I won't be using them again. I was really surprised about how cloudy the one clam spawning could make the tank. It looked like a large load although it cleared easily with a canister filter... I hope. I have a clam book that talks about rapid oxygen depletion. Yet, your experience is that it is not that big a deal? Thanks

It's not my personal experience. My five clams didn't spawn during the three years I had my tank up and running before I moved. I'm just basing that on reports from others. I had two croceas and three maximas but my largest clam was only about 4".

I still don't think a single maxima spawning in a 73-gal tank would cause serious harm.