sminnc - that sounds like a great temporary solution but i do think that it is best to find out where all of this phosphate is coming from in this tank. In my opinion, it is better to find the source and eliminate it, rather than put a bandaid on it right away. After all possibilities have been worked through than i think that stuff might be a good idea to resort to.
I agree, its best to find the source of any problem.
But this could work for the OP like it has for me so far.
My set-up is fairly new still. Couple of months or so? Lost track.
After it had run for a couple of weeks I tested for Iron and Phosphate. The only two tests I could come up with, more plant specific. Without looking into high dollar test equipment.
I found my Phosphate was high. And used the crystal clear. Which done what it was supposed to do.
So far, after a few weeks now. It has stayed around 1- 2ppm.
Actually I just added some Seachem Nitrogen for the first time, Sunday. Because my nitrate was soo low.
I did figure I'd be looking around more for a source problem. But so far, its turnt out to be a fix.
I'm assuming I brought it down, and now, along with everything else. The plants are keeping it low?