Po4 Red Sea Kit?

[calli]

I just wanted to know if anyone has done the Po4 kit low range and high range with the same sample.

I did the low range and got .08 and right after did the high range and got .17

Is there a reason this would be happening and do the salifert kits test better for Po4?

thanks all in advance.

 

[Pistol]

I use the hanna phosphate ulr and convert to po4, i find it is the most reliable but can get some wild readings to, I've tried almost all po4 test kits including the red sea
po4 is hard to get accurate readings

 

[calli]

Yeah I have always ready high. I did have a checker but it would read .20+ and my read sea kit would still read .08 or so.