balancing levels

5000 gallon vinyl pool

TA - 70 consistently since pool filled 1 week+ ago.
just tonight measured at 80?

PH floating between 7.2 and 7.4
just tonight measured at 7.0?

FC between 4 and 6.8 over the past few days with bleach added 1-2 x daily (not measuring bleach yet, just eyeballing right now) CYA 30-40

CC teetering between .2 -.4 (is CC this low a problem?) it goes to .2 when FC is closer to 7 and .4 when FC is closer to 4. Should I raise FC to about 10 to get CC to 0?

Why did TA raise? I haven't added anything but bleach.
Why did PH drop? It hasn't rained.

I'm still trying to get a handle on pool chemistry :)

Thanks

I forgot to mention there have been no swimmers in the pool. My readings today are generally where they were the other day.

FC 5.6
CC .4
TA 70
PH 7.6

My husband gathered my samples for me yesterday and today, and both times he took water from the pool in two different places than I do, I don't know if this has anything to do with it?

Quote:

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Originally Posted by purplegirl

5000 gallon vinyl pool

TA - 70 consistently since pool filled 1 week+ ago.
just tonight measured at 80?
The resolution of the test is 10 ppm so this is withing normal error range. Disregard this variation.

PH floating between 7.2 and 7.4
just tonight measured at 7.0?
I suspect testing error unless it is repeatable and the pH is now stuck at 7.0 It happens to the best of us at times.:eek:

FC between 4 and 6.8 over the past few days with bleach added 1-2 x daily (not measuring bleach yet, just eyeballing right now) CYA 30-40

CC teetering between .2 -.4 (is CC this low a problem?)
In a word no. Anything below .5 ppm is acceptable.

it goes to .2 when FC is closer to 7 and .4 when FC is closer to 4. Should I raise FC to about 10 to get CC to 0?
In a word no. Not really necessary but shocking wouldn't hurt if you want to. With a CYA of 30-40 shock to about 12 ppm.

Why did TA raise? I haven't added anything but bleach.
Don't think it did, sounds like normal testing variation that is within limits.

Why did PH drop? It hasn't rained.
My guess is that it did not and the comparator was not clean.

I'm still trying to get a handle on pool chemistry :)
You are doint GREAT!;)
Thanks

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One suggestion, use a 10 ml sample on the FAS-DPD chlorine tests instead of a 25 ml sample. You really don't need .2 ppm precision in most circumstances. The .5 ppm precision that you get with a 10 ml sample is more than adequate!

Quote:

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Originally Posted by purplegirl

I forgot to mention there have been no swimmers in the pool. My readings today are generally where they were the other day.

FC 5.6
CC .4
TA 70
PH 7.6

My husband gathered my samples for me yesterday and today, and both times he took water from the pool in two different places than I do, I don't know if this has anything to do with it?

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No, just sounds like normal testing variation and error that happens every so often. The fact that you retested and got your 'normal' results confirms this!

One set of out of line test results is nothing to lose sleep over. If they are repeatable THEN your water balance has changed.