I thought I'd chip in my experience, and maybe someone can give me some guidance/advice with my current issue.
Background:
Tank has been running for 190 days, 170 with inhabitants. I went through the typical diatom/slime bloom that cleared up with waterchanges and manual removal. Around month 3 some hair algae started to appear. Admittedly I wasn't super proactive on getting it out of the tank. Since late December (about month 4) I started doing waterchanges every 3 or 4 days with lots of scrubbing, manual removal, etc. I added GFO and GAC near the end of January, and kept up the waterchanges and manual removal, but I was losing the battle, and the algae was literally growing back faster than I was removing it.
I started dosing Algae Fix in late February. I did a total of 10 doses, during which I did 5 waterchanges and scrubbed the rocks each time. I continued running GFO/GAC, and monitored parameters.
My water has been stable since December:
nitrate undetectable
phosphate undetectable
pH 7.9-8.2
Ca 420 (+/- ~10 ppm)
dKH 9
Mg 1360
Current inhabitants are 2 ocellaris clowns, 1 orange spotted goby, 1 scooter dragonette, 1 chalk basslet, 1 pistol shrimp, 1 emerald crab, a few hermits, and about 10 assorted snails. Corals are mostly SPS, with two zoa colonies, a small galaxia, small brain, and small pipe organ colony.
Tank is a 40 gallon long that I made into an AIO. It has a 30 gal display volume, 5.5 gallon fuge and 4.5 gallon sump. I run a hydor slim skim dialed in to skim wet and have a filter floss compartment separating the skimmer output from the equipment compartment. I replace the floss at least twice a week. Lights are a DIY LED setup with 4 NW, 16 RB, 4 UV, 4 blue, and 4 green. I have independent control for each channel, and for the last couple months I have been running the RB, blue and UV for 12 hours per day, with whites and green on for 8 hours, although they are running at about 50% the power that the shorter wavelength emitters are.
Here's what happened with Algae Fix:
For the first couple doses I saw no effect, and fish and corals appeared fine. Around the 3rd or 4th dose I noticed that the glass wasn't growing much film. At this point my skimmer had completely ceased to produce anything, so I pushed the collection cup all the way down. Around the 6th dose I quit scraping the glass, since it was completely clean. About the same time I noticed a significant decrease in the stomatella snail population, as in I haven't seen more than 2 or 3 and I used to have tons. Similarly, the patches of coraline that were growing on the back glass slowly faded and are now gone.
The hair algae literally grew faster throughout the Algae Fix dosing. The one caveat is that the algae has also shifted from green to brown, but it has gotten to the point that I can brush a rock clean one evening and the next morning there will be 1/4 inch of brown hair covering it the next morning.
I stopped dosing 5 days ago. Yesterday my skimmer has started producing again, and today the cup was completely full of dark tea colored skimmate. I did a waterchange the day after the last dose and removed and scrubbed the two worst offending rocks. The brown hair has grown back slightly, but I really have to look to see it now.
I believe that my particular type of hair algae was unaffected by Algae Fix, and was able to capitalize on the nutrients available when the other algaes were being killed off. I have decided to go back to manual removal and waterchanges. Tomorrow I am getting a beefed up CUC consisting of ~20 more hermits, ~20 more snails and a pincushion urchin.
Throughout this experience my nutrient levels never fluctuated significantly, and my SPS corals grew very well. In fact other than the decrease in stomatellas there were no signs of stress in any of the inhabitants. I'm pretty sure that Algae Fix would have worked great if my particular hair algae pest was vulnerable to its effects. In my particular case, however, it seems to have made the problem worse.