I'm trying to grow macroalgae (Caulerpa prolifera and Halimeda), with no fish, corals or large invertebrates. Initially they did GREAT (for a month or more) but now all tanks are going through a stagnant period and being covered by fuzz (brown algae, red algae or hair algae?). While 2 tanks were possibly too crowded with plants, one tank has hardly any. At best they send out runners but no frond growth. I could test every available micronutrient, but since things don't seem to pickup when I change water I can't picture how lack of a nutrient or toxic concentration of some metabolite could be the perp. These are not supposed to be finicky plants. What could be the problem??
My conditions: I've been using instant ocean and have either a bubbler or pump (3 different tanks) and some lights on a 12/12 cycle. I've had live rock in there (for well over 2 months in some of the tanks) and tested chemistry for pH (~ 8.2) and presence of nitrates, nitrites and ammonia (all zero). I replace ~ half the tank water with fresh IO every 2 weeks and am using an ultrapure water source for 2 of the tanks (i.e. not tap water) and using PUR filtered tap water for another which is behaving similarly. I'm especially concerned because the asterina seem to have died which is pretty tricky to do I hear. The Halimeda tank had more hitchhikers...an Elysia tuca, some aiptasia, some tube worm, and some unidentifiables which seem to be OK up until now but I think are starting to look stressed (hard to tell).
My conditions: I've been using instant ocean and have either a bubbler or pump (3 different tanks) and some lights on a 12/12 cycle. I've had live rock in there (for well over 2 months in some of the tanks) and tested chemistry for pH (~ 8.2) and presence of nitrates, nitrites and ammonia (all zero). I replace ~ half the tank water with fresh IO every 2 weeks and am using an ultrapure water source for 2 of the tanks (i.e. not tap water) and using PUR filtered tap water for another which is behaving similarly. I'm especially concerned because the asterina seem to have died which is pretty tricky to do I hear. The Halimeda tank had more hitchhikers...an Elysia tuca, some aiptasia, some tube worm, and some unidentifiables which seem to be OK up until now but I think are starting to look stressed (hard to tell).