High Combined Chorine

[Clearly]

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.

[PoolDoc]

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.

[Clearly]

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

[chem geek]

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.

[Clearly]

Is there a link somewhere for the bucket List procedure? Should I wait to let it come down on its own or start immediately?

[PoolDoc]

The only reason for the bucket test is to see how much chlorine it will take -- but it won't change what it takes at all, or make it easier.

But, if you want to do the bucket test, do this:

1. Add 4 boxes of borax (20 Mule Team brand, added slowly to your skimmer, pump running) to your pool. The conversion process goes more nicely at a higher pH.

2. Get a CLEAN 5 gallon bucket and a bathroom scale. Put the bucket on the scale, and weigh it. Add enough water to the bucket to increase the weight by 33 lbs (4 gallons) - PF:3640

3. Half fill a measuring cup with plain 6% chlorine bleach. Add 1 oz to the bucket (about 14 ppm). Mix, wait 15 minutes, remix, wait 5 minutes. Test the chlorine levels.

4. If the CC level is higher than the FC level, repeat the dose and process.

5. Continue until the CC level begins to be LOWER than the FC level.

6. Add one more dose, then mix and wait 1 hour. Retest. If the CC level is less than 1/4 of the FC level, this is your approximate finishing point.

7. Multiply the number of doses by 14 to determine the total approximate dose required to clean up your pool. Divide this number by 2.7 to determine the number of gallons of bleach required, or by 3.7 to determine the pounds of 68% calcium hypochlorite required.

8. With a gunite pool, you can tolerate VERY high chlorine without a problem. Add 3/4 of the bleach (if you are using bleach) at one time. Do NOT cover the pool; do NOT let the heater or SWCG operate.

9. If you use cal hypo, you must add it slowly via the skimmer, but you must make SURE that there are no tabs, trichlor, ionizers or other chemicals or devices between the skimmer and the filter. Make SURE the heater & SWCG are off. You may need to backwash several times, as the lime dust accumulates on your filter.

10. Again, during this process you MUST leave the pool uncovered, the heater off, the SWCG off, and the pump ON.

[Clearly]

Ben,
I am confused where you are getting the 14 and 2.7 numbers. My pool is 22,000 gallons or 2,816,000 oz. Four gallons in the bucket is 512 oz. By ratio, if I add one oz bleach to the bucket that would be equivalent to 5500 oz to the pool, or 43 gallons of bleach. Your numbers say a 1 oz dose is equivalent to 5 gallons of bleach, which is much better, but I am not following the math.
Additionally, according to the pool calculator, adding one oz bleach to 4 gallons will raise the FC by 121. I am not trying to question your theory I am just trying to get the numbers to make sense in my head, as I am a dorky engineer! Thanks.

[Clearly]

So I have attempted the bucket test. I calculated that 5mL (0.16 oz) chlorine in 5 gallons of water (15ppm) is equivalent to 5.5 gallons of chlorine in my 22,000 gallons. So my dose in my bucket is 5mL. Here are the results of my bucket:
Before any chlorine: PH – 8.0, FC – 1.0, CC - 18.5
After first dose: FC – 17, CC – 21
Second dose: FC – 32, CC – 33
Third dose: FC – 46, CC – 36

I figured the FC was high enough even though the CC wasn’t 1/4FC. So three doses at 5.5 gallons per dose is 16.5 gallons, but I added 14 gallons to the pool (a little more than 75%). Unfortunately, I used the entire 871 reagent durin the bucket test and before I could test the pool because the chlorine is so high. I’ll have to get some more tomorrow before I can test again. Hopefully Leslies has some.
These seem like some high chlorine levels! Does this seem like I am on the right track?