TA - Pool Store vs TF-100

[Wizard19]

Moved into our home last summer with 3 year old pool. Had a service do the chemicals for 6 months but they didn't give it much attention. Been doing PPP. Water is crystal clear. Took in a water sample to local Leslie's Store this am and most readings matched mine (using TF-100). But they had TA at 120 and I have it at 70. All the other levels match with mine. I drained the pools four months ago to get CYA from "infinity" (lol) down to 45. I cleaned the TF-100 vials and did the TA test three separate times and still come up with TA=70. TA for me has typically been 80-90 but has tested lower the last month.I test the water every day. Haven't had to slam it since I took over the chemicals. We have the waterfalls on during the day and PH tends to drift up about .1-.2 per day. So I am adding some acid about every 2-4 days to stay withing 7.4-7.8 and liquid chlorine every 2 days. Do I trust my TA readings over Leslie's? It just seems to be such a wide variance.

FC 3-7
pH 7.5
TA 70 (TF-100) or 120 (Leslie's) ???
CH 250
CYA 45

 

[scdaren]

Trust your tests.

 

[Msch99]

Yup, trust yours. Perfect example of why. . I wouldn’t even try to compare, just makes you second guess. Your kit is more accurate than any pool stores and after a week or two you are more of an expert than the pool store employees! Especially with the occasional guidance of the friendly experts here!

On a minor side note, treat your CYA as 50. Halfway between 40 and 50 isn’t 45, the scale doesn’t work that way.

 

[mguzzy]

Looks perfect to me... the moral of the story that is told over and over on these forum walls is to not chase TA. The TA is a buffer and will find its balance with your pH. We only will recommend adjusting TA if its insanely high or low and it is usually and indicator of something else gone awry. You may see the TA rise and fall in relation to your pH as you adjust it to compensate for your water features. Its doing what its supposed to do.