Test results -- Looking for opinions

[Bellicusa]

I recently finished a rehab of a neglected pool. Have it filled and would love to get this balanced and happy.

Also, unless any test results make the pool unsafe for swimmers, I expect to host a graduation party tomorrow afternoon. Just something to keep in mind if that in any way makes a difference in the recommendations.

Using the TF test kit my results last night were:

FC - 11.5
PH - 6.8
TA - 100
CH - 90
CYA - 0
CC - .5

The pool is crystal clear now.

I aimed for a 6ppm FC last night and added about 300oz of 6% bleach. I am confused as to why I have such a high reading. Thinking maybe I didn't let the pool circulate enough after adding?

I added 7 lbs of stabilizer last night and expect my CYA to be in the low 30s. I believe I read I should wait a week to test that now.

I know the ph is too low...possibly a byproduct of adding the CYA yesterday. I see that adding Borax will bring the ph up, but also the TA which I believe to already be in spec. I also see that aeration will raise ph without moving my TA. How quick a process is that?

I welcome any other thoughts.

Thanks,
Anthony

 

[Bama Rambler]

Your FC is a little high to be swimming with a CYA of zero, but since you've added stabilizer and given that the sun will eat a pretty good bit of it off today you should be fine to swim tomorrow.

When I figure your pool I get a little more than 20,000 gallons. That may be your issue with overshooting. Keep a record of your additions and you can narrow it down over time.

Yes, wait a week before testing the CYA again but after two days assume it's in there and raise your FC level to match. If you use 20k gals to figure it, 7lbs would raise your CYA to 42 which is still a good number.

Since you want to keep or lower your TA, and raise your pH, aeration is your best method. At a pH of 6.8 with a good bit of aeration it should be a fairly quick process. I'd start it as soon as possible.

 

[coloeb]

A ph of less than 7.2 would be hard on the eyes of swimmers. Bama has listed everything else.

 

[waskydiver]

What's the lower range of the pH test?

If it's 6.8, how would you distinguish between a pH of 6.8 and a pH significantly lower than 6.8?

If you are confident that your pH is actually 6.8, then aeration is the way to go.

Otherwise, I would suggest you add Borax until you are able to detect the change (say... 7.0)... then aerate the rest of the way.

If you really are at 6.8, the change in TA to get you up to 7.0 would be negligible. If you are lower, you will want to get your pH up quicker than aeration will give you, and the greater effects of your TA would be less important then correcting your pH.

 

[JasonLion]

The lower limit of the standard PH test is 6.8. You can't tell what the PH really is when it reads 6.8 using that test. All you know is that it is 6.8 or lower. There are other tests that will read lower PH levels, though they tend to be less precise at normal PH levels.

 

[Bellicusa]

I certainly feel the need to question my own test results sometimes.

First thing this morning I started aerating the pool by aiming the returns up. Made a nice powerboat like wake at both ends of the pool.

Ran tests when I got home this morning and found my ph to be about 7.2. Was a little hard to tell for sure, but was lower than 7.5 but definately higher than 6.8.
Pleasant suprise ... and maybe I was a little off on my testing last night. Kept the aeration going to aim for 7.5.

Ran my ph test. Came back at 8. I like that number a bit. Figure I was at 11.5 last night. Whatever minor loss overnight and the day of sun. By 6PM the sun is off my pool completely so I can expect that to last the night as well as tomorrow.

Does the aeration explain the drastic change in ph or is it more likely I botched the test last night? Im fairly confident in tonights test so I dont believe the problem is there.

Thanks again,
Anthony