Just an update if anyone is interested. I have done many large water changes including the last one that was probably a 90% change and the phosphates are still well above 4ppm. I can only assume that the PO4 is coming from the substrate. I don't know how to get it any lower. Ive added three PO4 absorbing pads to my canister filter with little to no effect.
I'm at a lose at this point. I can only make sure I don't add any PO4.
tap is right at 1.0. I fluctuates slightly. I'm using the same test kit for tap as tank and i have no reason to believe it is faulty since I get two different readings.
I have a mixture of black sand black gravel and Eco-complete mineralized substrate. I know now that some of the PO4 is coming from the Eco-complete. I have used Flourish tabs in the past as well. I know between the two (substrate and Tabs) I increased the PO4 before I realized I had a problem. I just would have thought that it would have started to lower with as many water changes as I have done recently. Aprx 120% water change per week for several months. 3 - 30%+ per week every week religiously trying to lower PO4.
And maybe it has been effective and I'm just beginning to see some movement on the scale. My kit only measures to 5ppm, so if it was significantly above that I would not have noticed a drop for say 8 to 6