Watch your PO4 levels in relationship to how much algae is growing in your tank. Especially the back wall and power heads if you don’t clean them weekly. Too much algae will bottom out your PO4. If you dose PO4 without completely removing the algae, it just feeds the algae and PO4 will stay depressed. Once I cleaned up my water and made a concerted effort to remove all algae, my PO4 shot up. no algae to eat it. All the algae is gone now and PO4 stays between 0.13 and 0.18. I feed two good feedings each day and two good sized Nori clips a day and PO4 stays stable.I don't dose any of either anymore. So far, it's been ok, and levels have been decent. I'm scared of NeoPhos anymore after my last incident. I think I had phos already in the system and just wasn't reading it due to bad test kits. So when I was dosing, I dosed to high and that's what maybe caused the last fail.