crushed coral maxs out at 8.0-8.2. though it looks good and is pretty cheap it has its down side. your water will be milky white for a couple weeks. its sharp so loaches and catfish will not go in this tank without being scared and larger africanc can cut their mouths on it. i removed my CC after my fish started showing this. I suggest you add some CC in a filter bag to one of your filters and use smooth round gravel or pool filter sand. I just added 1 small bag to my canister filter and used pool filter sand it my 150 is around 8.2