I'm pretty sure we had a case of mustard algae (clear water but brown residue on the bottom, looked like dirt). I have been slamming the pool for more than 2 weeks now. Went through a period when the water turned cloudy, but now it's crystal clear and there is very little residue when I brush. (Just a hint of cloudiness in places) For a few days now the chlorine level falls 2ppm overnight. I've been waiting for that magic 1ppm as suggested in the OFCT, but it's just not happening.
Should I go ahead with the final mustard-algae-level slam now? Or should I keep waiting for the OFCT to show a drop of 1ppm or less?