cement rocks

So I was looking for some help I made some rocks using 50% oyster shells and 50% fast setting quikrete, I've have them in the tank soaking in freshwater, (air stone and wave maker running. After the first 24 hours the waters pH was 10.4 the next day after a water change and 24 hours after that...

Hello I've been in the hobby for quite some time and actually my very first tank I set up I used fast setting quikrete. I didn't cure it or anything in the tank it went! To everyone's surprised I never had an issue with it mind you that tank is long gone, and I'm finally setting up another tank...

Hi, I have some freshly made Portland cement mix rocks made up and I want to know if it is safe to add them to my reef tank? They've never been used in a tank before so I'm not worried about hitch hikers, and I already have lots of live rock in my tank so I'm not worried about treating them with...