Review on 🐠 Penn-Plax Deco-Replicas Granite Aquarium Ornaments - Authentic Stone Appearance - Fish Tank Safe for Freshwater and Saltwater - Ideal for Territorial Fish by Rachel Harris

I thought they would be slick - how wrong I was! I spent an average of 30 minutes on each file to fish-proof it. They are very rough - imagine the roughest sandpaper. Then add sharp sand. It appears to be made of rough quartz bonded with epoxy. Many holes are very uneven and even the insides are very rough. After putting them down, I kept washing them due to the insane amount of dust (toxic?). I then soaked them for over a week to wash off any chemicals that might have been present. They then ended up in my seawater aquarium, where I have always used activated carbon. This will cloud your water a bit and raise your nitrogen settings for a while (I think it's the epoxy. I love the way they look in my tank - my clownfish love them. Uffuuu! Anyway I wouldn't do it again and I just wish I knew what I was getting myself into beforehand.