stabilizing Ph by using crushed coral. hmmmmm??? Doesnt crushed coral increase PH? I added a coral substrate into my 20 gallon tank and it increased ph to 7.8 from 7.0, which I wanted. It has stabilized at that ph though. So i guess if you want your ph stabilized at 7.8 or higher..add crushed coral. Now the qestion is, how can I stabilize my 60 gallon tank at 7.0? The ph normally is 6.0 or slightly higher and I dont want to increase the ph to 7.8