R007 and pH testing?

[JimMarshall]

I was reading in pool school in the test kit directions that r007 or however many 0s there are is sodium thiosulphate to neutralize the chlorine so as to not effect the alkalinity test.

Soooo..... if a person had a FC near or over 10, could a drop of R007 be added to ensure that the high FC levels don’t skew the pH results?

 

[Donldson]

Nope. This has been tried and it did not alter the results: Accurate pH test during shock levels with R-007?

Problem is that when the thiosulphate neutralizes the chlorine, it raises the pH. That's why most pH tests only work up to 5 and Taylor up to 10 FC, it is difficult (costly) to neutralize the chlorine in a pH neutral manner.

 

[JimMarshall]

Thanks Donaldson, it hadn’t occurred to me to do a search when the brilliant (in my own mind) idea came to me last night. I’ve dropped my pH a bit through a huge blast of trichlor pucks, wanting to raise it back up to where I like to keep it, but my TA is low enough pH isn’t going to go anywhere unless I add something to make it go somewhere. The trichlor also has me >10 FC (though not by much) the last 2 days, so I can’t get a super accurate pH reading to know how much Borax to add.

My wife is hosting my sister’s bachelorette party here at the house tonight, so I want to get it taken care of, and the idea came to me last night. I had also tested it after making this post and he pH indeed read higher than it did before the test.