Clear Water, high CC

jccams

0
May 22, 2010
103
Dexter, MI
I just received the TF100 test kit to try and figure out why I can't hold chlorine in my pool. I have a 24000 gal vinyl liner pool in MI. I do not trust the pool store anymore so decided to take the advice on this forumn and go it by myself. I have an inline chlorine dispenser but have decided to try the bleach method and see if I can get my CYA levels to come down.

First check, CYA 80 FC .5 CC 3. I know that is bad and probably why I can't hold chlorine. I added bleach per the pool calculator last night to bring FC to 21 and will check again this morning and add more bleach as necessary to maintain FC at 21 until CC are below .5.

Question, my water is crystal clear. Is it normal to have CC so high but the water so clear? I did the test twice about 8 hours apart and had the same result CC = 3.

Any help/advice is appreciated.

Jeff
 
Welcome to TFP!

With a CYA of 80, your shock level is 31 of FC. Unless you bring your FC up to 31, it will be tough to clear your water.

This is why is would make good sense to go ahead and change out water in your pool to bring your CYA down. If you changed out 50% of your water, it should bring your CYA down to 40, a very manageable number. I would then fill it back up and retest your levels and then go from there.

It's also best to stick to bleach or chlorinating liquid as there is no CYA in those.
 
You added bleach to get FC to 21 and by morning FC was 0.5 and CC was 3 -- so something consumed the FC and left some CC. The sun and more chlorine will help get rid of the CC. You do want to drain and refill to control the CYA, and as suggested by 257WbyMag, 50% drain will be about right.
 
Why does the pool calculator indicate a shock level of 21 with CYA at 80? Changing out 12000 gallons of water is not in my budget so I need to work with what I have. As far as "clearing the water" I assume you are talking about high CC?
 
There's a difference between the Pool Calc and the Chlorine/CYA chart at high CYA levels. They both work but the chlorine/CYA chart will work a little faster.

One thing you do want to do is test and add as often as you can. Once and hour is recommended when starting the shock process.
 
Need some more help now. Noon FC 21 cc 1.5 added bleach to bring FC to 31. tested again at 5:30 FC 21 CC appeared to be 0, didn't look like the 5 drops changed the color at all. What do I do now, let the FC bleed down to about 8 and keep it there or raise FC to 31 again? Since CC seems to be 0 and the sun will go down soon I assume the FC level will stay fairly high overnight. What is a safe level to swim? I'd love to jump in now.

Thanks,
Jeff
 
I would do an overnight FC loss test to make sure all the algae is dead and organics cleaned up before lowering your FC level. When overnight loss is 1.0 or lower, and the CC level is 0.5 or lower, and the water is clear, and FC is below shock level for your CYA level you can swim.
 

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Took FC back to 31 for the night. CC was 1 so I don't expect the FC test to hold. When can I test PH to make sure it is O.K? Can I do this while I am shocking or should I get the chlorine under control then do any necessary PH adjustment?
 
the process can take 2-3days and sometimes longer. You're getting close. You can try the overnight test tonight. Also, make sure the pool is uncovered while shocking as sunlight will help burn off the CC along with the high FC level. If CYA is really 80...FC of 31 should not damage things.
 
With a CYA of 80ppm you can hold it at 31ppm for a very long time and not hurt anything.

In the big scheme of things it's not nearly as expensive as if you were adding all the stuff the pool store would have you add.
How many bottles of bleach have you added to date?
 
I think I am at 35 96 Oz jugs so far.

As far as CYA, pool store said 76 at opening and when I tested a week ago it was between 70 and 80. I should check it again, can this be done at shock levels? I am hoping by backwashing and maybe a couple of smaller drains I can get it down to the 60ish level.
 
6:30 FC 28 CC .5 added 1.5 96 oz 6%
8:30 FC 35 CC 1 don't know how that happened, shouldn't have raised it more than 3 or 4.
Going to do the FC loss test tonight

I also checked CYA again tonight. Tried it 3 times and got between 65 and 70. So I think I am closer to 70 than 80. Should I lower my shock level from the 31 I have been maintaining assuming the FC test does not pass tonight?
 

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