Ok researchers.. let me throw my experience out there.
As I've said before, my tank was in it's ugly phase and heading in the ugly direction very quickly. I started dosing Vibrant twice a week and it almost immediately knocked out my hair algae. My skimmer was going nuts and it was hard to keep it from overflowing with dark skimmate.
So I reduced feeding by almost 50%. Most of the hair algae was gone when I started getting Cyano. The hair algae never would go completely away but the cyano kept growing. On a recommendation, I added GFO and it initially seemed to knock back the cyano but didn't do much long term. Throughout this time I never saw any detectable nitrate in my system. I only had the Hanna low range phophate checker and never saw any detectable phosphate on it. To combat the cyano I started dosing 1ml/10 gal H2O2 for around a week with little noticeable change to my cyano.
At this point the cyano was having a very negative impact on my plating corals and my SPS's were very pale with almost no polyp extension. My hammer coral and pipe organ didn't look as bad but weren't doing well. My zoas were absolutely thriving. 2 of the 3 more than doubled their number of heads in 2 weeks. So I had signs of low nutrients based on my SPS's, high nutrients based on my zoa's, nothing detectable using my kits and a hard working skimmer. Out of frustration on Saturday I pulled my GFO, stopped dosing H2O2, and decided to stop using Vibrant.
Now, my cyano is receeding. The little remaining GHA is dying off. My skimmer is still working hard but I can go 2 days without emptying instead of doing it every day. No change in my corals but I expect them to be slower to respond. Not what I expected when I stopped using these products. My ultra low range hanna checker came in yesterday and I had 0ppb phosphates using it.
So this is what I am thinking....
The Vibrant worked great for me early and released all sorts of nutrients into my tank. As I worked through getting these nutrients removed I reached a break over point where I had almost no NO3 or PO4 left in my water. What was there was consumed by the Vibrant. This Vibrant biomass was used as food by my zoas and the cyano but couldn't be processed by my SPS's. When I would clean the tank, the cyano would break down and fuel minor GHA growth which was then consumed by the Vibrant and fed more cyano. Now that I have discontinued Vibrant, I am no longer adding the food the cyano was using and it is dying off.
Not sure if my observations help but thought I would lay them out there.
