High Combined Chorine

Recently I have:
- Opened pool for the first time as it was built new in the fall, and the balanced chemicals
- Lowered PH, used stain removal product, raised PH with Borax after stains removed.
- Chlorine was low after stain removal process because SWG was turned off. Then added fresh water to raise the water level, which lowered chlorine to nearly 0.
- After about two hours of kids swimming the water was green and my CC was 2.
- I tried to shock it by bringing the FC up to 15. It wouldn’t go above about 8ppm for the longest time. It took 31 gallons of bleach to get it up there. The next day the pool was clear and the kids swam in the evening.
- Now the FC is back down to 2, but the CC is about 15. So it seems to have made it worse.

Why didn’t that work? What can I do to burn off that amount of CC? Is there another option to buying 30 more gallons of bleach? The water looks clean and doesn’t have much of a chlorine smell, but it doesn’t have that crystal clear sparkle that it had when it was properly balanced.

Thanks.

What kind of test kit are you using? I would think that a CC of 15ppm is unlikely. Did you fill from a well?

I got the Taylor 2005 when the pool was built. I did the dilution method (1.8mL) and it was darker than 5 when I added the thrid drops - about 1 after the second drops. I am on a well, but added softened water from inside the house.

If you buy the Taylor K-1515 which is a stand alone FAS-DPD tester, you'll basically have the K-2006 that we recommend. You can get it through the test kit page in my signature below. It would be a good decision to get it.

OK. I bought the supplemental kit via your link, but regardless I am fairly certain that I have high CC. I like to get this taken care of ASAP as the weather is supposed to be cool this week. What is the best process for eliminating high CC?

The way to get rid of CC is to maintain your chlorine at shock level as consistently as you can. But, in the case of a pool with a metals issue like you have, shocking can cause metals to fall out of suspension and stain. I am going to ask Ben to pop in here on your thread and advise you so, sit tight for now.

Watermom,
I received the K-1515 test kit yesterday and checked the chlorine levels. Here it is:
FC- 2.0, CC – 22 (44 drops of the 10mL test), CYA ~ 30, PH – 7.6 (goes up about .05 per day)
Will some of the CC burn down on its own? It has been 8 days since I added 31 gallons of bleach due to the green color and have been running the SWG since the FC got back down to 2.0-4.0. I am inclined to wait a while because my water looks good and doesn’t have much of a smell, if any. I have been reading about people adding 100+ gallons of chlorine to get their CC down. I am afraid to start the process! Isn’t there a bucket test to estimate how much chlorine it will take? Thanks.

Wow! That's the highest CC I've seen. I'm going email Chem_Geek, and see if he has any ideas.

Meanwhile, please re-read the instructions on the K-1515, and make sure you don't have a testing error.

The 1515 results are consistant with the dilution method, which showed a bright 15+. Unfortunately, I am confident the results are accurate.

It sounds like the pool was opened with ammonia and that you haven't gone through all of it yet. The FC is probably bleed-through from the high CC and not really FC. Keep adding chlorine until the CC starts to decline and you start holding an FC reading. If you want, you can do a bucket test with pool water to estimate how much more chlorine it will take.