Man made rock

StephenMcn · Dec 23, 2021

Hi all, I have just gotten an amazing piece of unique fake rock that is huge. This piece of rock was made for a upcoming movie and was in a tank (freshwater I presume). I do not know who constructed or made it so I can't ask the question. I have drill Ed a few holes through the centre of the structure to see if there was any metal support poles but didn't find any (still could be though) is there any test I can do to see if its safe. I seen online a fizzle test with a nitrate test solution and if it fizzles its no good but this was only freshwater test. I have currently broke a small piece off and have it in a little container filled with sw and I've tested for nitrates and po4 now and will do another test next week to see if any have elevated. Is there ajytelseni can do to make sure this doesn't wipe my tank. I have attached pics

JNalley · Dec 23, 2021

Hmm, it's hard to say. All of the manmade reef rocks have Aragonite sand and stuff in them which keeps them pH Neutral. If that thing is just cement that's been molded and painted/pigmented, it's likely to cause problems in my experience. I'd also be leary of the pigments used, some pigments are perfectly fine for freshwater but not acceptable when exposed to a saltwater environment. It would be a gamble to use, for sure. But, if it's the shape you're after (because the rock will eventually be covered with algae and such anyways), you could make a silicone mold of it, mix up some aragacrete and recreate it.

Rmckoy · Dec 23, 2021

The colour is throwing me off and curious what else is in it or on it.
For the most part many made reef rocks are Portland cement , sand , oyster shells .
and course salt that will dissolve when curing to leave plenty of holes and craters .

curing Takes for ever with many water changes .