Sudden phosphate drop in high nutrient system

[JayDenver]

Hi All! I've lurked around the forum for awhile and finally posting for the first time.

My tank is a softie only 40G breeder with minimal live stock, 2 clowns and a cardinal. I want to start getting more serious about the corals I keep and start slowly going into the LPS and hopefully SPS.

My question is, for a tank that has always run at a high nutrient level, how many days should it take me to drop phosphates from .3 PPM to .15PPM (goal is to get them to sit around the .1 range long term but working on baby steps). Ive looked over a bunch of prior posts, some look to say to take it super slow, some have dropped it fast with products like Neophos. At the .3 PPM, my zoas, leathers and gorgonian all looked healthy and growing, but I do have algae issues that I have to battle during my weekly WC otherwise i probably wouldnt have tried to drop it.

I added half the recommended amount of phosguard, and phosphate has dropped from .3 to .22 in the last 2 days - which the corals don't look like they appreciate since they are accustomed to the higher nutrients. Should I aim for a lesser .02 drop per day? Should I stop now and see if they adjust to the .22 or let it keep riding?

I appreciate any insight you have to offer!

 

[Randy Holmes-Farley Verified Community Expert]

Your phosphate level may not be any problem as it is, but lowering phosphate too fast very often is an issue.

Going very slow would be my advice, and 0.02 ppm per day when at 0.2 ppm seems OK. No faster, IMO.

I'm also not a huge fan of phosguard due to aluminum release, but unless leathers close up, it is probably OK.