High CC (>6.5 ppm). How to add free chlorine to burn them?

[tortose]

I am new to the website. I start to own a swimming pool from this year. After doing googling work, I have found the useful forum, from which I have learned a lot.

Here is the story about my pool. All the measurements haven made using Taylor 2006 kit.

On 5/5/2017, I opened my pool.Below was the parameter I got:

FC 0
CC 0
CYA 0
pH 7.8
TA 130 ppm

The low CYA make me believe that the CYA was decomposed into amine during the last winter because I saw previous owner had been used pucker to maintain the pool.

For the slamming of my pool, I first turn off the inline chlorinator. Every day I had to keep my closed because the CyA level zero so that I can keep a high concentration of FC to slam my pool.After I used almost 24 gallons of 10-12.5 liquid chlorine. Below are the measurements that I got on 5/13/2017.

FC: 4.5
CC: >6.5
CYA: 0
pH 7.3
TA: 150 ppm

I believe that I still need to add much more liquid chlorine to the pool to burn the CC. I would like to know how I can use 10% liquid chlorine to efficiently burn the CC. My pool is vinyl liner and has 20000 gallon water. Here are my questions:

1. What is the maximum gallons of liquid chlorine (10% ) that can be added every time to burn the CC without damaging the vinyl line and other equipment?
2. After adding the liquid chlorine, after how many minutes should I measure the CC after adding the liquid chlorine?
3. How frequently can I add the same amount the liquid chlorine to the pool?
4. I did not add CYA, therefore all the Slamming has to done at the dusk or when the pool is covered. I am going to use pucker to elevate the CYA levels after the pool slamming is finished. Does the strategy works?
5. In the coming winter, what procedures I should follow to prevent CYA from decomposition into amine?

Thanks for your suggestion.

 

[Texas Splash]

Hello and welcome to TFP! Your situation is not all that common, but not rare either. You are at a point where you need enough FC to break-through that barrier. Here's what typically recommend:
- Based on the % of bleach you are using, use the Poolmath calculator to increase FC to "10". Test in 10 minutes to see if you've retained at least 50%. Basically, you want the FC to hold between 5-10. If it dropped too far in those 10 minutes, increase FC right away back to an FC of 10 and repeat this process until you see the water respond and begin to hold FC.
- Once you are able to hold FC between 5-10, then you can increase CYA with stabilizer for an initial target of "30". At that point, also increase FC to "12" and begin your SLAM (link below).

I should've mentioned, before beginning all of this, ensure your pH lowered to at about 7.2.

Hope that helps.

 

[tortose]

Thanks you suggest. I will follow your instruction. Can I know what procedures I should follow to prevent the complete decomposition of CYA during the next winter?

 

[jblizzle]

Re: High CC (>6.5 ppm). How to add free chlorine to burn them?

You can also pick up an ammonia test from a pet store to see how high your level is. That will give you some idea as to how much bleach you need to add.

The decomposition is not well understood but it seems like it occurs in pools over the winter where there free chlorine drops to zero possibly due to not being closed correctly. And if some bacteria somehow get into the water possibly from dirt.

 

[Texas Splash]

Generally here at TFP, we refer our users to the following:
Pool School - Closing (Winterizing) Your Above Ground Pool
Closing an in ground pool

You'll see a couple common themes between the two pages, but in the end, every pool has its unique conditions. Ironically, some owners don't do much at all and almost never have this type of issue. Even the best maintained pool can have a perfect storm of sorts between organics, water temps, and chemical decomposition. Usually though, if you follow the instructions on those pages they do a good job in mitigating such problems in the spring. And as we always say here at TFP ... "Close late and open early" to beat the algae and scenarios such as this to the punch.

I hope that helps. Good luck with your 10-min drill today. Hang in there, it will work.

 

[tortose]

Thank you all for the very useful advice. I feel very luck I have find out the right forum and get to know so many kind anonymous friends.

 

[tortose]

Should I continue to slam or not?

After the winter, all the CyA was converted into ammonia. During the opening of my pool, I used a lot of liquid chlorine to remove the ammonia. Below are the parameters that I have got (Note: Taylor 2006 kit was used for the measurements and the ammonia test strip was purchased from Walmart).

Ammonia level: 0.25-0.5 ppm
FC: 16-18 ppm (keep the concentration for more than 12 hours).
CC: 0.5-1.0 ppm (using 10 mL solution method: After 2 drops, the pinks color is gone. The concentration has not changed for 2 days under a high concentration of FC 10-18 ppm)
pH 7.6 (No changes for 3 days)
CYA (Not detected)

Water is very clear.

My question is should I continue to slam or not? 1.0 ppm is still high. Why CC can not be lowered further when 18 ppm FC was kept in the water? What is the reason?


Thank for your help.

 

[jblizzle]

Re: Should I continue to slam or not?

Why is your FC so high if you have zero cya? You don't have a cover on your pool do you?

 

[tortose]

I have kept high FC because I want to remove the 0.5-1 ppm CC. But the level of CC does not change. I want to know if I still need to add more liquid chlorine.

 

[Texas Splash]

I want to know if I still need to add more liquid chlorine.

Basically... yes. From everything you started out with this season, you don't appear to have successfully performed or completed a "SLAM" (link below). If you go back to post #2 above, you'll see the steps you should've taken which by now would've helped a lot and resolved some of your problems. You really need to follow that 10-min drill as noted above in step #2 and then perform the SLAM until you pass all 3 SLAM criteria.

 

[Texas Splash]

And to piggy-back on what Jason noted above ......... your FC is exceptionally high (at the moment) only because you have no CYA to protect the pool and liner. You never want to increase the FC that high with no stabilizer to protect everything. That's why the instructions in step #2 are so important. The CCs will resolve themselves naturally when you follow the SLAM process.