Two different Chlorine readings

ckwinters · Oct 3, 2018

I am using the TF100 test kit and when I use the complete kit chlorine measure I get 3.5ppm but when I use the little quick test that came with the kit for Chorine/PH it reads in the 5-10 range. Just wondering about the accuracy of which test to follow. Is there something else that throws off the accuracy of either test? We filled this pool early September and I'm still working the CYA up and am now at about 40. PH is just below 7.8 so I need to figure out where to buy the muriatic acid.
Thanks for any info!

triptyx · Oct 3, 2018

The quick little color block test is only good enough to tell you that there is some amount of chlorine in there. Use the FAS-DPD kit (the powder and drops) for an accurate chlorine reading.

Depending on your state, you can get full strength (31%) muriatic acid at Lowes or Home Depot. You may have to look in the painting section. Double check the strength - they sell "pool" acid but it's 15%.

JamesW · Oct 3, 2018

Did you do the CC part of the test?

ckwinters · Oct 3, 2018

Good to know about the quick test. I thought I may have way over chlorinated!
I did not do a full range of tests. I did play with some of the other tests when we first filled but we've been pretty crazy backfilling and trying to get ready for decking so I've mainly been targeting the cya and chlorine. The pH has crept up over the month...is this because of lots of rain? If I remember correctly my CC was 0 when I tested. I've been trying out different brands/strengths of bleach and I'm averaging about .5 gallon per day.

The water looks great but it's about 65-68 degrees so only my 8 year old has been swimming!

Dirk · Oct 4, 2018

Ha! Boy or girl? Only my 3-year-old girl will get in the pool now. Which means I have to, too! But that's around 78°. Yours is getting into 68°?!? Yikes. My 6- and 9-year-old boys are the babies!! They stopped getting in around 81°!

ckwinters · Oct 4, 2018

We have all boys but the older two wouldn't even think about it! With such a late fill we never got up past 75 degrees in the water but we all still swam when it was that temp.

Dirk · Oct 4, 2018

Had to be done!

triptyx · Oct 4, 2018

New plaster will cause pH rise. You definitely want to keep an eye on that and maintain pH between 7.2 and 8.0, or keep it at or near what your PB said you should for warranty purposes. The first year you'll see a lot of pH rise and will need to be aggressive about testing and adjusting with muriatic acid to counter it.