Lowering combined chlorines

[mknauss]

Looks good. I doubt you have a reagent issue.

 

[SR71P52]

Looks good. I doubt you have a reagent issue.

Thank you. The other strange thing is that my k-100 test shows a very light shade of yellow on the TC test. With a CC this high, shouldn’t it be very dark? The test does darken over time, but not over 5ppm level like I would expect.

 

[mknauss]

The OTO could be gettting washed out due to high TC. Just keep adding chlorine and testing FC. Do not mess with testing CC.

 

[SR71P52]

The OTO could be gettting washed out due to high TC. Just keep adding chlorine and testing FC. Do not mess with testing CC.

thanks, I’ll continue to test FC and add bleach. Are there any negative effects of adding so much bleach? I’ve added 9 gallons today and just went to get some more. Just seems like a lot.

 

[mknauss]

No detriment as long as you are staying at or below SLAM level FC.

Can you fill out your signature? The information really helps us help you.

 

[SR71P52]

No detriment as long as you are staying at or below SLAM level FC.

Can you fill out your signature? The information really helps us help you.

No problem! I think I’ve added a signature now.

interesting discovery.. I did some reading and I think my issue is high ammonia. The CYA level was extremely high(150ppm) at close last year. When I reopened, the CYA was zero and the FC was also zero. I’ve read that Cya can be converted by bacteria to ammonia over the winter. I have some aquariums and tried out my reagent based ammonia test on the pool and found levels of 10ppm+, which would be ridiculously high even for a very poorly cared for aquarium. I’ve dozed 14 gallons of 10% bleach so far and my FC levels are around 6ppm currently... I will keep trying to raise it to a shock level. Would partially draining the pool be a better option given the high ammonia?

 

[mknauss]

I was afraid of ammonia. It takes at least 10 ppm of chlorine added to eliminate one ppm of ammonia. So I suspect it would be better for you to drain your pool. Or at least most of it

I did not press that at first as you said you had CYA in the water and also you were measuring FC. If you have ammonia, both of those are typically 0.

 

[SR71P52]

I was afraid of ammonia. It takes at least 10 ppm of chlorine added to eliminate one ppm of ammonia. So I suspect it would be better for you to drain your pool. Or at least most of it

I did not press that at first as you said you had CYA in the water and also you were measuring FC. If you have ammonia, both of those are typically 0.

They were both zero upon opening. I added some dry stabilizer that brought my cya back up to 45 or so, and it’s been holding there since. I can try diluting the sample to get a more accurate reading of the ammonia in the water tommorow, but it appears to be around 10ppm. I also tested the tap water and zero ammonia showed up there. I was able to get the FC to settle around 5... after adding 18 gallons of liquid chlorine today (this seems like a ridiculous amount!!). I’ll check these parameters again in the morning. Hopefully things start to move or draining the pool might be the only option. Thanks again!

 

[SR71P52]

Update:

I tested the water this morning and only had 2ppm of FC. Tested my ammonia and it was still off the charts. I diluted the sample by 1/2 and 1/4 to try to get a reading, eventually settled on around 25ppm of ammonia as my current level. According to what you said, this level would require 250ppm of FC, or almost 70 gallons of liquid chlorine! In the end we decided to drain most of the pool to get rid of the ammonia. Would I be ok to drain some of the pool and refill and do this in several cycles? I don’t want to risk damaging the plaster. I Will restart the water with the TFP method when it’s full again. Thanks .

 

[mknauss]

You can do it in several cycles. Biggest threat in your area is the pool shell lifting from the ground due to ground water. But doing half and then half again will get your ammonia level down to where you can kill it off with just a few gallons of bleach.

 

[SR71P52]

You can do it in several cycles. Biggest threat in your area is the pool shell lifting from the ground due to ground water. But doing half and then half again will get your ammonia level down to where you can kill it off with just a few gallons of bleach.

Thanks! I will do that. Since I can test the ammonia levels, any recommendation on what ppm level to stop at? I was thinking once it’s under 3ppm. That should be able to be taken out with under 10 gallons of bleach.

 

[mknauss]

That sounds like a plan.

Remember for the future -- if you close in the fall with high CYA, and test 0 CYA when opening, run the ammonia test first. You can use your actual test kit, or just follow the process in the Ammonia - Further Reading article.

 

[SR71P52]

Update!

Drained and refilled most of the pool over a few cycles.. got the ammonia level down to about 6ppm. Decided to stop there and start the SLAM process. I ended up needed about 12 gallons to reduce the ammonia to zero, after which the pool started finally holding chlorine! I’m currently holding a level of 12ppm FC to SLAM. But it’s looking very good so far! Thanks again.

 

[SR71P52]

The water is holding chlorine for a few hours at 30ppm CYA. Should I raise the CYA a bit more? Also my PH is extremely low.. under 6.8. I assume this is due to the reaction of chlorine and ammonia causing hydrochloric acid. Do I need to add PH up if my TA is 70?

 

[mknauss]

If TA is 70, the pH should rise from aeration. Though I am concerned for your heater so you should consider adding a touch of Borax to raise the pH back to the 7's. This will raise your TA a little.

Keep your CYA at 30 ppm until you pass all three criteria for a successful SLAM process.