I just started dosing this stuff tonight into a heavily stocked SPS tank. I dosed 9ml into a 90 gallon display with a 20 gallon sump, estimating 90 total gallons of water. I noticed no immediate signs of any problems dosing the regular, non-marine Algaefix. Polyp extension is stellar tonight.
I'm dosing to combat what has been dubbed "ghost algae", the extremely fine whitish-tannish filamental algae, bacteria or fungus (I don't believe it was ever actually determined). I keep an extremely low nutrient level in my tank and this stuff seams to be thriving as it very easily traps detritus. Even with heavy carbon dosing, heavy skimming, weekly detritus cleanings and a lot of GFO usage, this stuff is taking off. I had a small amount of bryposis, grape caulerpa and chaetomorpha algae which have all died off. We will see if this Algaefix can kick the ghost algae.