First TF-100 Test Results! Questions/advice...

capricatunes · Jun 10, 2020

I just got my test kit and did the full battery (I think). Results:

FC: 1.5
CC: .5
TA: 150
Ph: 8
CH: 1
CYA: 40

Pool: ~30k gallons, vinyl.

I used pool math to calculate bleach addition, and addition of low n slo I still had. I have read the ABC’s of Pool Chemistry and most of the articles in the 101 area / getting started.

Questions:

1) The first time I did my CYA test, I noticed that I added a bit too much solution to top off the bottle. Probably 2 cm? When I ran the test, my result was 20. So, I did the test again being sure to get the levels of liquid as close as I could, and the result was 40. Does that difference sound right? Should I test again tomorrow? How critical is the exact liquid amount for this test? The disparity between those two tests concerned me (largely out of ignorance) so I’m asking to ensure I’m not doing something wrong here.

2) I still don’t quite understand CC. Is the fact that it is .5 a problem? I added 128oz of 12.5% bleach (sodium hypochlorite), which is what pool math told me to do. But, I just wanted to make sure that I don’t need to do anything else.

Thank you!

splashpad · Jun 10, 2020

Well done so far! (Can you add your pool and equipment details to your signature? Thanks!)
1) I know that the CYA reagent and pool water sample should be equal, not sure how much it actually effects the results... It's a reflectivity test, so the LIGHTING conditions should have more effect on the result.

2) .5 is acceptable, unless it shows up on every test. Then a SLAM would be considered.

splashpad · Jun 10, 2020

Also, with a PH of 8, you will need to get some muriatic acid and bring that down, keeping it around 7.4/or so (not lower with vinyl)

IceShadow · Jun 10, 2020

Some pools just keep a small amount of CC. Mine did last year, and this year I don't have any. Unsure why, but 0.5 isn't a concern.

capricatunes · Jun 10, 2020

splashpad said:
Also, with a PH of 8, you will need to get some muriatic acid and bring that down, keeping it around 7.4/or so (not lower with vinyl)

Thanks. I had some low n slo, and added that to target 7.4-7.6 using pool math calculator.

My Ph *does* seem to creep up, and the TA seems high. So, I may need to lower the TA...? I posted another thread about that awhile ago (wasn’t sure what TA was all about). As I now understand it, you should only lower TA if Ph regularly increases. Ph does seem to climb on me...but, maybe that’s normal?

capricatunes · Jun 10, 2020

IceShadow said:
Some pools just keep a small amount of CC. Mine did last year, and this year I don't have any. Unsure why, but 0.5 isn't a concern.

That’s great to hear. Thank you!

capricatunes · Jun 10, 2020

splashpad said:
(Can you add your pool and equipment details to your signature? Thanks!)

Done.

splashpad · Jun 10, 2020

capricatunes said:
Thanks. I had some low n slo, and added that to target 7.4-7.6 using pool math calculator.

My Ph *does* seem to creep up, and the TA seems high. So, I may need to lower the TA...? I posted another thread about that awhile ago (wasn’t sure what TA was all about). As I now understand it, you should only lower TA if Ph regularly increases. Ph does seem to climb on me...but, maybe that’s normal?

It is normal for it to "drift" up with activity in the pool. The problem is when it swings high & low quickly