I found an old thread in here that said that the Walt Smith rock affected KH but I can't find any articles or information about this. My 38 gallon is entirely made of this rock (with only 1 small piece of real live rock) and I have narrowed down my corals doing terribly to this or my Hydra 26 HD lights (which I first believed the issues to be from). We are KH buffering every single night, and I am wondering if the KH is affected by these rocks. After almost one year we finally have a tiny bit of coraline on the back glass. All parameters are FINE. I test weekly and do water changes every 4 weeks. I don't see any growth on the Walt Smith rock at all. Nothing. I do have 1 small piece of real live rock which has pods and life, but nothing on the Walt Smith stuff. I feel like the rock is the problem but it's so hard to tell without replacing all of it. Does anyone have long term success with this rock that can share any challenges that they faced along the way? I don't want to remove all of it, but if it comes to it, I will since this is the first tank that I just can't get anywhere with. I've had 5 SW reef tanks before (2 of which had LED setups and did GREAT!!) so this isn't my first rodeo.