Hach Test Kits 2248 Vs. 2250

[JerseyReef]

Craig/Randy, et al:

I have a few questions regarding the difference between the two Hach Phosphate Test kits 2248 and 2250. I spoke with Mike Kirda on RK and he recommended the 2248 kit. I had also passed this by Boomer as well. He mentioned the 2248 kit and the 2250 kit.

I asked Boomer the difference between these two kits and he mentioned that the 2250 kit is a complete phosphate kit not just an orthophosphate kit, like the 2248 kit. The 2250 kit will measure organics and meta's as well.

I know the cost of this kit is high ~$120. In retrospect, wouldn't this kit be the more obvious choice in measuring phosphate, if in fact total phosphate is what we as aquarists should be measuring in the first place?

 

[CraigBingman]

Mike,

Both total and inorganic phosphate are of interest. In my experience, there is so little polyphosphate in reef systems that it isn't really worth running an additional test for that parameter.

Hach's total phosphate test kit is OK, but people should know that they will need to do a little chemistry in order to measure total phosphate. The sample is digested with potassium persulfate in the presence of sulfuric acid for about thirty minutes at high temperature. The sample is then neutralized, and restored to its original volume, and then you measure the phosphate concentration in that prepared sample.

It is a little more than most people are willing to do, and it does involve playing with concentrated acid, base, a strong oxidizing agent and a hot sample. If you are willing to do all of those things, then the total phosphate test kit is probably for you.

Craig