I think that tanks can be too "clean". I think this is whay many Zeovit users have problems sometimes. I believe that Zeovit causes a tank to be very "clean" and that the regulation of additives to keep that system going is a fine line. In such a system, changes become magnified in effect. I used it for quite some time with success, but then had some problems that I found were not related directly to Zeovit, but rather magnified by the "clean" environment. I stopped using Zeovit and let me tank "go", so to speak. I have found that growth improved and colors got worse, initially. The colors reverted after a few months on some corals, stayed worse on others and got better on a few. Some corals never changed at all. BUT, losses from either tip recession or base recession were much fewer.
All of this just reinforces something that I have always known. Stability is more important.