question on diy live rock

[jeff5347]

Hey guys. I didnt know if anyone attempted this or successfully made some. My question is on cure time. I have them sitting in tubs w circulating water and change it out every day or 2. I keep getting this film on the surface which in assuming the concrete is leaching out. The clear tub rocks ( first 2 pics) were done w salt the blue one no salt used. How long should it take until the water doesn't get this film. On pH in using a fw test kit and the tap water is 8.2-4 and after the rocks sat it is in the 10s ( deep purple color in fw kit). I'm kinda Leary on throwing these in the tank as i don't want a mass extinction. Forgot, they have been in the tubs for 2 weeks now and don't plan on removing them til after this month

 

[Mebbid]

I'm not sure on cure time but things can be sped up by adding distilled vinegar to the water. What type of cement did you use to make them?

 

[jeff5347]

Portland cement, salt and crushed coral on Tue first 2 pics. PC and pool filter sand on the last 2. The cc ones came out really nice