This is an old thread, but figured I'd chime in...
I'm not running a Zeovit system with Zeolites. But like such systems I do have very low phosphates and nitrates. Cannot detect it with my Salifert kits. I owe it to skimming and running an algae turf scrubber. Given that similarity, I thought Id give CV as shot.
I began dosing 1 drop into my 40g system twice a week at night. KZ recommends roughly twice that dose daily. After a month my corals appeared unchanged, so I moved to a drop every other day. I think - it is subjective - that my corals responded with better color. So after a few months of that I moved to the recommended 2 drops per day.
The result? Within a week I was observing colors on some of my corals that I've never seen. For instance I've got an acro that was all blue but within a week was blue and bright green. And birdsnests that have historically suffered in my care, appear to be mounting a solid recovery - previously bare skeleton being colonized by polyps again.
Can I attribute this with certainty to Coral Vitalizer? No. But it sure looks like it.
Oh... it's worth mentioning, I received a
pink stylophora from Vivid just as I had increased the dose to a drop every other day. I'm NOT an experienced SPS keeper, and I was afraid that this beautiful pink coral would brown out in my care. Far from it! If you check that link, that's what the coral looked like when I got it. Now it is MUCH pinker - deeper pink, better coverage. I'm assuming the CV made the difference because - as I said - I'm not an experienced SPS keeper.
Here's a recent pic. It's actually pinker than this shows, but I'm limited by both my camera and lack of photographic skills.