I need help with measuring PO4

[Delphinus]

... And I still am not really getting repeatable test results. Andrewsk, when you get your unit can you please get in touch with me? I would like to compare test results (we can test your water, my water, or both).

Surgeonfish, .. are you not noticing particulates floating in the vial if you only swirl for 60 seconds? Because I check my vial every time after 60 seconds and there's nowhere near complete dissolution of the powdered reagent. I have to swirl for a minimum of two minutes, or more, before I stop noticing particulates floating in the water.

At any rate, I'm now convinced that either my tank has wildly fluctuating PO4 levels (unlikely and implausible, but I'll accept that it's not impossible), or that either my test unit is defective or I have a bad lot of reagents (boy am I glad I bought 100 of them ).

Before I send the unit back to the vendor however I would REALLY like some confirmation. So if anyone can help me test some PO4 I would be grateful.

Or I guess I can spring for another $100 and buy a D-D test kit. I love bludgeoning money for this hobby. (Oh man I am so frustrated...)

I actually found an aquarium water testing service. You mail in a sample, they email you back a complete panel. Sort of like how if you have a water well you're supposed to get it tested if you drink the water, same sort of thing. I've emailed them for a quote plus a reference sample kit, we'll see how feasible this option is. Failing that I might even call around town to see if any of the chem labs are willing to do a panel for me... I'm sick and tired of not knowing the full story of what my tank phosphates are.