When to react to changes in the test results.

[pb4uswim]

Excluding CL and PH, I thought the rest of the numbers usually stayed pretty stable. Below are two test results about a month apart. Question is basically whether or not I should react to the most recent numbers. Or, should I wait a week and retest and see where things are heading. My concern is that the CH went down a lot. I know with a fiberglass pool, that may not be a big concern, but it makes me wonder - did I do the test wrong (twice), are my regents going bad, was there something different about the water (temp, circulation . . .) or, is it time to add more calcium? Also wondering about the salt.

Note, the April test is just after opening. Since then, we’ve only swam a few times as the temp is not yet warm here. I’m not concerned about the numbers in general, but wonder when to think about tweaking any of the numbers. Thanks.

Results from 4/9/21
FC 3.5
PH 7.2
TA 70
CH 250
CYA 70
Salt 3200

Results from 5/16/21
FC 6
PH 7.3
TA 70
CH 150
CYA 60
Salt 2800

 

[zea3]

Do you have an autofil on the pool? Have you had a lot of rain? How old are the reagents, and where do you store them? Do you use a speed stir for your tests? CYA, CH, and Salt all went down, and those are values that usually only go down with water replacement. I would try and determine first if a leak or rain is responsible for a some water replacement.

 

[pb4uswim]

The pool is new last year so the regents are just coming up on one year. They are stored in my house. There hasn’t been a lot of rain. We opened it and they cleaned out the pool and vacuumed to waste (brought their own pump and just dumped the water in my yard) and since then, the pool has remained at about the same level.

Note that the tests are both from this year and only a month apart. My last full test of last year was in September 2020 as follows:

FC 7.5
PH 7.7
TA 85
CH 200
CYA 70
Salt 3200

 

[zea3]

Do you have an autofil?

 

[pb4uswim]

Do you have an autofil?

No.

 

[IceShadow]

CYA, CH, and Salt have all dropped. It would correspond to water being removed through backwashing or a leak and adding new water without those things. If you haven’t added water, then the only thing I can think of is testing error.

 

[pb4uswim]

CYA, CH, and Salt have all dropped. It would correspond to water being removed through backwashing or a leak and adding new water without those things. If you haven’t added water, then the only thing I can think of is testing error.

I'm guessing some sort of testing issue. I'll run the pump overnight and test in the morning. I've been running the pump for 5 hours every morning to get chlorine, but I did test after the pump was off for a couple hours. Maybe that's all that's going on. Of course I'll double check my testing work because there's always the possibility I just messed up.

Thanks.

 

[Bperry]

I'm guessing some sort of testing issue. I'll run the pump overnight and test in the morning. I've been running the pump for 5 hours every morning to get chlorine, but I did test after the pump was off for a couple hours. Maybe that's all that's going on. Of course I'll double check my testing work because there's always the possibility I just messed up.

Thanks.

Are you testing every day or just once a month?

 

[pb4uswim]

Are you testing every day or just once a month?

The pool hasn't been used much so I've just been testing the Chlorine and PH frequently (every couple days). The full test was just those two times since opening in April.

 

[IceShadow]

How long did your pump run before you tested the water at opening?

 

[pb4uswim]

How long did your pump run before you tested the water at opening?

A long time. I think a full day (24 hours) at least.

 

[IceShadow]

Hm, so probably not stratifying water.

 

[pb4uswim]

I’ll post some new numbers tomorrow.

 

[pb4uswim]

So, my guess is that the first set of numbers were off - the first tests upon opening the pool. I've redone the tests a couple times, making sure that the pump had run several hours, and I'm coming out about the same. I'll post my most recent set of tests in a new thread to ask some follow up questions. Thanks for the help.

Results from today
FC 6.5
PH 7.5
TA 70
CH 150
CYA 60
Salt 3000

It's worth noting that the salt being different by 200 or 400 is really only the difference between one or two drops of the reagent. Easy enough for me to be off by one or two drops. I'm now comfortable that 3000 is an accurate test result. Not sure what happened to the CH and of course we all love the CYA test.