I had some white CaribSea Instant Aquarium sand in three of my tanks: a 3g, a 2.5g isolation tank, and a 10g community tank. While cleaning the 2.5g, I noticed the sand had turned completely gray and was giving off a horrible sulfur smell. I dumped it all out and thought maybe it was just because the 2.5g was too small or something. But now I'm noticing the sand in my 10g is turning gray in places also. I've lost two cory cats in that tank, could it be the sand? And yet I had cory cats in the 2.5g for isolation and they did fine, it wasn't until they got into the 10g that they died. I'm getting concerned because I have my very dear betta Sherman in the 3g tank. So far the sand in there looks okay but now I'm worried.
What could be causing the sand to go bad? Could it be killing fish? I made sure not to put too thick of a layer in the 10g and there was less than a half inch in the isolation tank. Any help or suggestions would be welcomed.
with sand you should move it around every few days, little pockets of bacteria can develop if it isn't disturbed and can kill you fish. I would take your fish out, mess up the sand so all the bad stuff is released, then do a 100% water change. You could also start over with new sand if you wanted.
Since it's already turning gray, maybe I should start with some new sand. Double-drat. I wonder if what happened was my cories who died hit an air pocket of that toxic gas and it just dropped 'em right in their tracks. Since the cories are always rooting around in the sand, that is.
You'll go broke if you replace the sand all the time lol! You have to rake it every few weeks to remove those gases and bacteria.. I put up a link to how to make a little sand rake in the i have no self control thread, see if that helps. :D