TFT vs. pool store test

[GoPokes43]

I'm seeing significant and consistent differences on TA and CH tests with my new TFT kit compared to testing by Leslie's.

Today, results were as follows, which is very consistent with pool store tests over the last few months and the TFT kit over the last month since I got the kit:

Test -- TFT vs. Pool Store
FC -- 3 vs. 3
CC -- 0 vs. 0
pH -- 7.7 vs. 7.6
TA -- 50 vs. 90
CH -- 475 vs. 275
CYA -- 40 vs. 50

Either way, the CSI is about the same. Also, I did just check TA with my Pentair test kit that came from the pool builder. It's at 50. So, maybe the pool store is really that far off every time over the last few months.

But, I'm wondering if I got bad bottles for the TA and CH. Any thoughts?

If my TA is truly 50, which I lean toward thinking that is the case, I'm really concerned about accuracy on the calcium because if it is 275, then I have close to -0.3 on the CSI when my ph is around 7.5.

 

[mknauss]

Welcome to the forum.

Quit having your water tested at the pool store. They do not have the same commitment to accuracy you do. You have no idea if there equipment is calibrated, cleaned, and in working order.

Take care.

 

[BasicTek]

Welcome to TFP!

I did the same thing when I 1st started testing, 2nd guessing my results and going back to the pool store, everyone kept telling me to stop... trust my own results... Well after getting comfortable with my own testing I found that Leslies was consistently wrong with CH, CYA (especially if over 100) FC (especially if over 5). In my case they were usually pretty close with PH, TA, and CC. I fully trust all my test results now, I've added the chemicals, and seen the precise changes I expect using pool math. Now on occasion, I go to Leslies and have them test to see just how wrong they are, and watch them give unknowing people bad advice, sell them lots of chemicals they don't need, at prices that are too high.

...and -.3 CSI is usually a good CSI. If you can add your information to your signature as per this getting started section

-Tim

 

[GoPokes43]

Thank you. I think my signature should work now. I haven't fully completed it yet.