K2PO4 vs KH2PO4

["Greger Lindstrand" <greglind at algonet_se>]

This is very intresting. 
I was given some KH2PO4 by a friend. I have not been able to get K2PO4.

I've found that the Hagen PO4 testkit don't work on KH2PO4, while the Sera PO4 testkit does.
Does anybody have a clue as to why this is so?

Is K2PO4 better than KH2PO4 or does it not matter which one, one use in a planted tank?

What kit do you use Travis when you test?

< snip>
> I bought the wrong stuff. I know I should have ordered K2PO4 instead of KH2PO4 for dosing potassium. I have KNO3 for dosing nitrate. I know I can use KH2PO4 for phosphate dosing, but what should I do about K-potassium dosing? Should I just assume the plants are getting enough from the KH2PO4-mono potassium phosphate and KNO3-potassium nitrate?
<snip>

Best regards
Greger Lindstrand