reagents

[Corrinna]

Hello all,
First let me tell you how great I think this forum is....I began reading and educating myself here 2 yrs ago, this is my third summer using the BBB method. This year was by far the easiest so far! So thank you, thank you, thank you!!! My question is are all reagents created equal?! I cannot afford a taylor test kit yet and have an hth 6-way test kit. I ran out of the CYA reagent and would like to get more......will the replacement reagents I find on different pool supply websites work?
Thanks,
Corrinna

[AnnaK]

Hi Corinna,

I've used two different CYA tests. One, the Taylor from my test kit which uses 14 ml water and 14 ml CYA reagent. The other was a CYA test I bought at Leslie's, called Blue Devil. It had a larger test cylinder but still used 1/2 water and 1/2 reagent.

My conclusion is, the reagent is the same. The primary ingredient is melamine. I bought a pint of the reagent from Amato Industries for $6.86 plus shipping. I've used it in both test cylinders with half water, half reagent, and the results came out the same.

[chem geek]

Taylor uses a carefully pH buffered reagent with melamine because melamine cyanurate at normal pool pH is actually soluble to around 20 ppm so you need to force the pH much lower to get an accurate reading. Though I trust Taylor in doing this right, I wouldn't be so sure about cheap test kit brands -- one can check the pH (with wide-range tester -- even test strips is OK in this case) of the mix of pool water with reagent in each case and it should be quite low.

[AnnaK]

Thanks for the details. There's something in my memory about acetic acid being one of the reagent ingredients. Is that correct? That would explain the low pH.

[chem geek]

It was some sort of organic acid, but I don't think they specified which one and I don't think it was acetic acid. [EDIT] Anna listed the MSDS contents for me and it only had acetic acid (which is an organic acid) but at fairly low concentrations along with sodium acetate so that could be used as an buffer to have the pH be low. [END-EDIT]