dissolving rock

[KLN]

In my second tank, which is in early fishless cycling phase, I put a rock I thought had been in an aquarium in the past. Then the rock started to dissolve. I took it out, but some of it was aleady dissolved in the tank. Could that have put something unhealthy in the water? How should I check for it?

 

[reefrunner69]

Do you know what kind of rock it was? Could it have been a very dried lime rock that just started to erode with the water and waterflow?

If your not certain what kind of rock it was, I would do a large, if not total water change and run GAC.

 

[KLN]

No idea what kind of rock. It was off-white, and is white now. It dissolved rapidly, leaving sediment on the sand in the tank, and a lot of cloudy matter when I removed it. If it was limestone, would that be harmful to fish?

 

[reefrunner69]

If it was limestone, would that be harmful to fish?

No, LR is pretty much a limestone rock. That is what it sounds like to me, the limestone was dried and brittle and started to erode when introduced to water.

FWIW, it's not a good idea to add things to your tank if you are uncertain of their origins.