Hey guys! I tried my hand at making a "concrete reef" using Garf's recipe...sort of. I used type I/II Portland Cement in Ash Grove color. I mixed it with Tahitian Moon Sand and some coral fingers. Then I just formed it in more moon sand mixed with some epsom salt. The salt dissolves out leaving little holes. However, it has taken a while for the salt to dissolve out (it's been a week and some is still hanging on). I have been soaking my rocks in fresh water for about a week, but treated them with Hydrochloric Acid first and so far my pH hasn't been outrageous. However, I have been taking my rocks out and rinsing them in tap water every day. Then I put them in my sink, fill it up, let it sit for a couple hours, drain it, re-fill it etc... My pH was pretty high but it's gotten much lower already. I'm definitely going to continue to cure it as I am in no hurry use it. I don't have any fish in my tank and considered curing it in there, but I'm afraid it would kill my live sand/rock. I want to make sure it's good and cured before letting it anywhere near my tank.
I took some pictures of my rock and I'm pretty happy with how it turned out. Pretty neat looking in my opinion. I understand that it doesn't look "natural." Before you comment on how it doesn't look "natural," please understand that "natural" wasn't what I was aiming for when making my artificial rocks.
Okay so I can't get the site to let me upload to this post for some reason, so just view the rocks by clicking the link below. Feel free to put in your two cents if you want.