Low, ultra low or high phosphate checker?

[Fishyj]

Ok, I am confused as to why there are 3 phosphate checkers. Am I missing something here? Which one should I get to check on phosphate? Looking at it, I would think the low range one would be good for checking. Looking for opinions.

 

[Randy Holmes-Farley Verified Community Expert]

Between the Hanna checkers, I would recommend the ultra low phosphorus, the HI 736.

 

[Fishyj]

Thank you.