Thanks that helps.
I just happened to have that Leslie’s DPD 2-bottle test from pre-TFP days so I used it all summer after the pool behaved, so essentially all summer.
Recently ran out, so started suing the OTO.
I simply found the DPD 2-bottle test easier to read/ more accurate, based on my testing with both the OTO and the FAS-DPD minutes apart (just like I did when I fist started using the DPD 2-bottle test early in the summer).
With the OTO I was under or over chlorinating, without creating a problem, just seemed to be silly to under or over chlorinate (I’m sure the same is true when I used the 2-bottle test, just less so, because I measured it on several occasions); for the price of 1 more bottle per summer, I can more accurately chlorinate, not for accuracy sake, for bleach expense & algae issues.
It could just be my eyes, but my guess is that others would have similar findings.
And yes, that 2-bottle test has another bottle to measure CC, which I never did, for CC I use my test in the TF100 kit
Thanks again for the great info.