My new phosphate test showed up today and I tested .25 3 times. I've read that gfo is thought to contribute to pm in clams. Is seachem's phosguard or brightwell aquatics extrax phos ok to use? I've also heard that these are aluminum based and can cause other issues, beginning to think I read too much I have the double reactor from BRS, po4 remover goes in the first chamber followed by carbon in the second. I use kalk in my top off, have read that kalk will help precipitate po4 as well. I change 15 percent of my water weekly. I feed pe mysis and nls pellets daily as I have wrasses, anthias, and a copperbanded butterfly. All other parameters are rock solid.