well, algae consumes nitrates and phosphates during photosynthesis, which is why macroalgae is a good thing to have. once the algae dies, though, it returns all those nutrients to the water, in effect promoting nutrient pollution in your tank. if you can remove it, do so...get snails if you have to, and remember anytime you can export nutrients, take advantage of that opportunity. also, it kind of sounds like this algae may actually be bluegreen algae (a.k.a. cyanobacteria). if this is the case, the presence of bluegreen algae usually indicates a preexisting nutrient and/or circulation problem. so, if you have dying algae, it could be causing a problem, but the reverse is also true...a nutrient issue could be causing your algae problem. reduce feedings, make water changes with high quality salt and RO/DI water and see what happens! hope this helps
