sportparadise
Member
Thats also what i am afraid of too. I am taking rock out today(most of it) Going to scrub them and set them in another tank blackout and run carbon and gfo along with a powerhead for a few days and then see what they look like.well if you blackout the tank, you take away one food source. If you run aggressive GFO and carbon during that same time period you "have" to make a dent because you're stripping another source although you're competing with the GHA for it. This all assumes that there isn't a constant source of phates in the tank from somewhere. I guess that's the smoking gun.
I hate GHA. Try taking a rock that is pretty covered out....and put it in a bucket of new water and heat/circulation and see if the HA dies off. I would be worried that your rocks are supplying the food and if that's the case you need to ditch them.