Combined Chlorine High

[StratDoc]

Hi all,

I am a new to the forum so thank you in advance for letting me post to the community.

I was gone for a week and my chlorine got out of balance. I was using the local pool stores for water testing which after finally purchasing a commercial Taylor kit 2006 found out that their tests were way off. Here is the situation as of this morning.

FC 7 ppm
CC 20ppm
alkalinity 120
PH 7.0
CYA 60

The problem is that I cannot maintain FC throughout the day, but CC seems to keep going up every time I shock the pool. Last evening no FC, but CC of 22. Added 6 lbs of shock last night and this morning I have the results posted above. I have read that I need to keep shocking the pool until CC is gone. How is it best to do this and how much shock do I need? I have not tried to increase PH at this point until I get the chlorine issue under control.

Thanks,

Robert

[PoolDoc]

Hi Robert;

I was using the local pool stores for water testing which after finally purchasing a commercial Taylor kit 2006 found out that their tests were way off.

That's not new to us!

Do all the following:

1. Tell us, as exactly as you can, what chemicals have been added since opening.
2. Tell us, if you remember, what your stabilizer level was, last fall.
3. Go to Walmart, and get 8 boxes of 20 Mule Team borax. Begin adding them, 2 boxes at a time slowly, via the skimmer, with the pump on, spacing doses at least 4 hours apart. Quit when your pH reaches 7.6 - 7.8
4. Tell us EXACTLY what chemicals you have on hand (mfg, exact product name)
5. As best you can, complete our pool chart:

Pool Chart Entry Form
Pool Chart Results

We've seen more of the high CC problem this year, than in all previous years together, likely because of the weather. The most common cause is bacterial bio-degradation of stabilizer to ammonia, but in such cases we don't usually see positive CYA levels. However, if you've been using stabilized chlorine to shock, you may have add that 60 ppm CYA. However, there are other possibilities, such as the used of a large dose of "Green to Clean" type products.

The reason for a pH increase is that, regardless of source, the end products CC's are oxidized to, are nicer at high pH levels.

By the way, if you have a cover, leave it off. CC removal is a combination of chlorine + solar UV + aeration. Covers cut back on sunlight, and stop off-gassing.

[StratDoc]

I bought the house late last fall and the pool was open so I never closed it. I also didn't test during the winter but kept the pump going and tabs in the trichlor feeder.

Since opening used Jack's Magic copper and scale stuff to remove a calcium build up over iron staining. I have since used an asorbic acid "stain free" twice to remove a rebuild of stains around nozzles, on steps, and pool sides and used approximately 3 bottles of jacks blue stuff. I have kept trichlor 3" tabs running continuously. I have shocked the pool once per week until this past week when it would not hold free chlorine. Early in the week used approximately 10 lbs of shock, still would not hold FC. Pool supply company suggested OxyShock. Used 4 lbs Wednesday evening - I understand it can give a false CC level. I also changed the sand in the Hayward filter this past weekend. I just tested the pool water a 3:15 with the following readings of FC and CC

FC - 0
CC 16
Ph 7.0
Alkalinity 120

=========================

Chemicals on hand: 40 lbs of shock with no stablizer. 4 lbs of Ph increaser. 8 lbs of Alkalinity increaser. 2lbs of stain free and two bottles of sequestering agent called "metal out".

[StratDoc]

Added 3 lbs of shock last night. This morning readings are

FC 6
CC 20

[PoolDoc]

3. Go to Walmart, and get 8 boxes of 20 Mule Team borax. Begin adding them, 2 boxes at a time slowly, via the skimmer, with the pump on, spacing doses at least 4 hours apart. Quit when your pH reaches 7.6 - 7.8.

Do that.

• Then, once the pH is up, begin with 10# doses of cal hypo, each evening.
• Make 110% SURE that is your trichlor feeder is COMPLETELY empty, and add the cal hypo via the skimmer.
  (Cal hypo and trichlor react together in very bad ways!)
• Run your pump 24/7 if you are not already doing so.
• Clean your filter when pressures are 5-7 psi greater than the 'clean' pressure.
• Replace the gauge if it's broken.