Testing for chlorine with the FAS/DPD test gives me results 2.5 times higher than the pool store, test strips, or color comparison liquid (OTO) tests. Bioguard analysis said 1.6% total chlorine, but the FAS/DPD showed 4.0%. Any help would be appreciated. Thanks
Chlorine test method accuracy
- Thread starter froggy1869
- Start date
You are filling to the 10ml line, adding a scoop of powder, counting the drops and swirling between additions, then doubling the number of drops for your reading?
You can safely toss out the results from the pool store and the test strips.....they are worthless.
The OTO test is never terribly accurate but it is always dependable.
If you performed the test properly, the FAS/DPD result can be taken to the bank :-D
(It's ppm (parts per million), not percent)
The OTO test is never terribly accurate but it is always dependable.
If you performed the test properly, the FAS/DPD result can be taken to the bank :-D
(It's ppm (parts per million), not percent)
Yes, 10 ml plus scoop of DPD, dropwise addition of FAS, multiply X 0.5. Having a chemistry education and career, I'm understandably curious about accuracy of test methods. So the statements of "worthless" or "take it to the bank" aren't as quantitative as I'd like. Nevertheless, I'll go with the FAS/DPD as the gold standard. thanks for the feedback. (Yeah, I know it's ppm not %)
I was just like you when I started and finally gave up (trying to compare all the different test results) and committed to only using the FAS/DPD test and my pool has been perfect for 3 years