[nvladik]

Originally Posted by taricha

here's what I would recommend:
either Seachem flourish - phosphorus. It's derived from potassium phosphate.
or find a high P fish food, one that has fish meal as the first several ingredients.

what I actually did:
I used a miracle grow 4-12-4 (N-P-K) derived from ammonium phosphate, potassium phosphate and urea, nothing else.
Then I read a suggestion in the macroalgae forum that the simultaneous presence of nitrate, phosphate, and ammonia can cause cyano and although I was very pleased with macro growth, the cyano growth is unacceptable.

So to get away from ammonia & urea I tried changing to an industrial cleaner from home depot: Trisodium Phosphate (TSP)-
It's 80% trisodium phosphate dodecahydrate, and 20% sodium sesquicarbonate. 6% phosphorus by mass. I ran the numbers based on amounts I intended to add, and although my chem knowledge is pretty limited, there was nothing in there that put up red flags for me. My KH was a little low anyway, and I could stand for my pH to rise a little.
It hasn't helped with the cyano growth, and my halimeda seems to be dying back, so I'm probably going to pull the plug on the TSP.

I read bunch of stuff in the macro forum, they do a lot of work with controlling nutrients other than with fish food.

Thanks taricha. I picked up Aquavitro Activate, same concept as flourish and will give it a go in small doses first.