What is a good phosphate test kit to use?

[scyphozoa]

I am wondering if you can recommend a good low end phosphate test kit. I don't usually test for phosphate and have only used the Salifert kit in the past. Unfortunately, with that kit the color differences can be subtle and it is not sensitive enough to show small changes. Also, how significantly can media such as Phosban decreases levels of phosphates vs. doing more frequent water changes. Is it worth worrying about such media binding with calcium that one works so hard to add?

 

[Randy Holmes-Farley]

How low are you wanting to read?

I like the Hach kit PO-19 from www.hach.com
but it can't read much below 0.02 ppm phosphate

 

[scyphozoa]

Is that the one you use? Will it go down to levels where one can determine if phosphates might not be the major problem causing algae problems?

Also, how much calcium does media like Phosban remove....enough to worry about?

 

[Randy Holmes-Farley]

GFO like Phosban does not remove appreciable calcium.


I use the Hach kit, but bear in mind that if you have a lot of growing problem algae, the kit may show no phosphate because the algae is taking it up as fast as the phosphate up. That is how growing macroalgae can reduce phosphate, and microalgae can do it just as well if there is a lot of it.