First-time SLAM with unexpected CC and pH

[mbender71]

I'm a first-time pool owner who decided to take over pool maintenance from a pool company that I felt wasn't providing the best possible service. I'm an engineer and love technical challenges. I thank this website for providing the knowledge and confidence to take on this task. I started three months ago and immediately went to move the pool to the TFP method. One of the things I disliked was the staining on the 16-year-old plaster. Using Jack's Magic Copper treatment three weeks ago, I removed much of the staining and was quite happy with the results. I extended the treatment to make the most of it, and Jack's Magic technical support was very good. Now, it just so happened that as I was about to take the pool out of treatment and do my first SLAM, along came hurricane Ian that dumped 14" of water on our property. The pool was already light turquoise though I could see the bottom of the pool before Ian (slightly murky). I knew I was going to SLAM the pool after treatment and now definitely after this hurricane. I set up the pool to the prerequisites Thursday after the storm passed (no more rain) and started my first-ever SLAM yesterday morning. Here are my starting numbers (taken from my TFP-Pro Salt kit and double-checked with my calibrated pH meter) :

pH: 7.28
FC: 0.5
CC: 9
Alkalinity: 60
CYA: 50
Water Temp: 74F

Between 10 am and 8 pm yesterday, I performed 4 SLAMs at regular intervals using 10.5% liquid chlorine. I also brushed the pool twice yesterday as well. Each time I SLAM'd (at regular intervals), the FC residual increased, so I had to add less chlorine. The total amount of chlorine added yesterday was 5 gallons, and the pool is between 10k and 12k gallons. This was expected. Before I lost daylight, the pool water was much bluer, BUT the pool was very murky (I could not see the bottom of the pool). I went to bed, leaving the pump on and hoping that in the morning, it would be a little less murky. That was not the case.

This morning (right now), I tested the FC, and my result was 7 ppm. I am troubled, though, by the color of the water, which has returned to light turquoise. I tested the CC yesterday 2 hours after the first slam, and it read at 30 ppm. I tested the CC this morning, and it read at 42 ppm. WOW! I hope these CC readings are ok since to me, they are very high, though the FC is tracking as expected. As my worry increased, I decided to test the pH just now. I only performed the pH test using the Taylor and another chemical kit I used before the TF-Pro (just to be sure). The results from both chemical kits show a pH over 8, and this REALLY worries me. I know the SLAM instructions say that pH testing is difficult during this time, but I have read in the threads where some people were able to test pH when FC was under 10 (which is my case). I know the chlorine becomes ineffective after pH 8.2 (or so), BUT the pool is super cloudy, the CC is increasing, and the FC drops each time I SLAM.

I'd like to kindly ask the experts here if my first-day results are ok or if perhaps I'm seeing something else in the picture (perhaps ammonia though I have no idea how it would get in the pool since only my wife and I have used the pool the past 1.5 years, and we don't use it as our bathroom *smile*). Just thinking crazily right now and appreciate any comments!

I'm off to sweep the pool, clean the filter, and do another SLAM. Thank you so much!

 

[HermanTX]

So very happy that you survived Hurricane Ian and now dealing with the aftermath of lots of rainwater and debris.

One of the steps of a SLAM is to maintain your FC at SLAM level which is 20ppm for a CYA of 50. Have you ever reached that goal? You mentioned a CC of 30ppm which seems to be a testing error. You test CC after you determine the FC level. Are you positive on your testing procedure?

Please test FC and CC again and post results.

EDIT - since you have a Apera PH 60 meter, you should be able to test pH.

 

[Mdragger88]

The cc’s is crazy - so crazy I think it may be a testing error.
Let’s be certain you are doing the test correctly.
10 ml sample
Add 1 scoop of dpd powder- sample turns pink
Swirl while adding r-0871 , each drop counts as .5 ppm (don’t squeeze the bottle, just allow the drops to fall - about a drop per second) the bottle should be completely vertical.
Once the test goes clear record the result as FC & proceed with the next portion of the test adding r-003 in the same manner.
Once the test goes clear record the result as cc (each drop counts as .5)
*Important * If you allow the sample to sit it will turn pink again- this doesn’t mean to continue adding drops to get back to clear. Doing so makes for invalid results.
You don’t want to rush through the tests but you can’t wait around- you must move on to the cc’s test immediately after completion of the fc test.

 

[Mdragger88]

If you’re sure you did the test correctly,
It is also possible that the Jack’s stuff is interfering with your testing. That stuff likes to stick around- especially if you used alot of it.
The remedy is to use TC as your gauge for the Slam
Fc+ cc = tc
In that case you likely have a very high tc level at this time.
If you think you have a high copper level which caused the stains in the 1st place (usually due to using products with blue in the name) you may want to look into doing a no drain water exchange to remove the copper permanently as well as the by products from the jack’s stuff (sulfamic acid) then proceed with slam to deal with the algae.

Draining - Further Reading

www.google.com

@JoyfulNoise can explain a little better than me

 

[mbender71]

The cc’s is crazy - so crazy I think it may be a testing error.
Let’s be certain you are doing the test correctly.
10 ml sample
Add 1 scoop of dpd powder- sample turns pink
Swirl while adding r-0871 , each drop counts as .5 ppm (don’t squeeze the bottle, just allow the drops to fall - about a drop per second) the bottle should be completely vertical.
Once the test goes clear record the result as FC & proceed with the next portion of the test adding r-003 in the same manner.
Once the test goes clear record the result as cc (each drop counts as .5)
*Important * If you allow the sample to sit it will turn pink again- this doesn’t mean to continue adding drops to get back to clear. Doing so makes for invalid results.
You don’t want to rush through the tests but you can’t wait around- you must move on to the cc’s test immediately after completion of the fc test.

Hi there, and thanks for the reply! Yes, that's exactly how I perform the test (I've done so many that it's definitely memorized). I forgot to mention that I use the Taylor SpeedStir for all my vial tests. I will admit that since the color of the solution after adding R-003 is so red that I put the drops in at probably .5 sec each since I have to count for so long *smile*. I have also experienced the "sit around and turn pink again," but only because I was recording the data before I cleaned the vial and noticed it turned pink again. I read on the forums that it was expected, so I didn't worry. Just finished my first SLAM of the day along with filter cleaning. I had to add 1 gal 1qt of 10.5%. The water is quite pretty as it's very light turquoise and bright, but it's VERY murky. Thanks again!

 

[mbender71]

If you’re sure you did the test correctly,
It is also possible that the Jack’s stuff is interfering with your testing. That stuff likes to stick around- especially if you used alot of it.
The remedy is to use TC as your gauge for the Slam
Fc+ cc = tc
In that case you likely have a very high tc level at this time.
If you think you have a high copper level which caused the stains in the 1st place (usually due to using products with blue in the name) you may want to look into doing a no drain water exchange to remove the copper permanently as well as the by products from the jack’s stuff (sulfamic acid) then proceed with slam to deal with the algae.

Draining - Further Reading

www.google.com

@JoyfulNoise can explain a little better than me

Hi again! Yes, the Jack's Magic Copper treatment will indeed mess with FC readings and I just re-read the fine print on the treatment instructions that I should use TC instead for 3 to 4 weeks after the treatment. Well, that would make sense! I just started the third week after treatment. I will admit, the water in the pool "looks" like water that just has a lot of chlorine in it. I'm going to do another FC test right now and report back, though I'll probably hold off on the CC for a couple of hours since I'll probably have to count to 120 now *big smile* Many thanks again!

 

[mbender71]

So very happy that you survived Hurricane Ian and now dealing with the aftermath of lots of rainwater and debris.

One of the steps of a SLAM is to maintain your FC at SLAM level which is 20ppm for a CYA of 50. Have you ever reached that goal? You mentioned a CC of 30ppm which seems to be a testing error. You test CC after you determine the FC level. Are you positive on your testing procedure?

Please test FC and CC again and post results.

EDIT - since you have a Apera PH 60 meter, you should be able to test pH.

Hello! Thank you so much for your kind sentiments. Although central Florida did get its share of damage (mostly via flooding), I feel more for those that lived in Ft Myers :-( I have to admit that I never tested the FC right after adding the chlorine. I always relied on Pool Math to calculate the amount of 10.5% chlorine given my CYA of 50 (which is FC of 20 ppm). Perhaps I missed that in the SLAM pool school *ugh*. Since I *just* did another round of SLAM, I will wait for 2 hours before taking another FC, CC, and pH. I'll use the PH 60 meter this time as well. I think @Mdragger88 is on point regarding having just used Jack's Magic Copper Treatment 3 weeks ago and that I should be using TC for my FC. The water is pretty (not like an algae green). It just looks like water that has a lot of chlorine in it (it's very bright and light turquoise). Thanks for writing!

 

[Mdragger88]

So it isn’t cloudy?

 

[mbender71]

So it isn’t cloudy?

Oh, it's cloudy but a pretty turquoise cloudy. Not a green or dark green *yuck* kind of cloudy. It looks like water that has "too much chlorine kinda cloudy," to be honest. I just took a picture of the pool since a picture is worth a thousand words! I can actually see the robot at the bottom of the deep pool now. Perhaps things are getting slightly better since early this morning. Soon I'll be doing an FC + CC test to get the TC. I might do a pH as well, but I'm not sure if I should do anything with that IF the readings come out over 7.8. I'm not smart enough to know how muriatic acid would react with a super high TC :-(

 

[Mdragger88]

Don’t adjust ph based on the drop test.
The ph meter reading shouldn’t be affected by the high fc/tc if you’re really worried about it & want to check it. I would still wait until tc is at around 10 to adjust ph so you don’t accidentally over do it. Here’s the info on the Jack’s stuff & testing

Acid - Further Reading

www.troublefreepool.com

 

[mbender71]

I decided to wait 3 hours before testing the FC, TC, and pH. The results are pretty darn amazing. Amazingly scary that is!

FC: 11.5
CC: 60
TC: 71.5
pH: 9.25
Water Temp: 76F

So, I guess my Leslie's 10.5% chlorine and/or whatever the chlorine is attaching to is making my pool *extremely* basic. Lesson learned about doing SLAMs right after sulfamic acid treatment. I think I will treat my TC as my FC and let the chlorine levels naturally drop. No more SLAMs though I will perform an OCLT tonight. Although I'm not able to trust FC tests at this time, I think I will still use them and treat the values as relative values and not absolute values. Hopefully, the CC will gas off sooner than later and my pool will start losing its "murkiness." Thanks to everyone who replied and to anyone who chimes in on this!

 

[JoyfulNoise]

It’s the excessive Jacks Magic treatment. It’s sulfamic acid and sulfamic acid reacts with chlorine to form N-chlorosulfamate. Chlorosulfamate registers as CCs.

You’re going to need to perform your SLAM based on TC. Unfortunately it’s going to be painfully slow to clear because chlorosulfamate is only a mild disinfectant and a weak oxidizer. It’s also going to take weeks for sulfamate to break down and your FC to return to normal.

 

[JoyfulNoise]

The CCs will not “off gas” as the chlorosulfamate doesn’t leave the water. Every time you add more chlorine, you will create chlorosulfamate from the free sulfamate anion. Over time, the sulfamate anion will hydrolyze into bisulfate and ammonium anions. When that happens, the chlorine will then start to convert the ammonium in nitrate/nitrogen. When that happens, you’ll start to see the pH and TA drop.

I suggest you keep the pH below 8.0. You can target 7.8 and then let it rise from there. You can use the acid demand test if you have it available to determine how much acid to add to get to 7.8. I wouldn’t go any lower because the sulfamate breakdown will eventually start to lower pH on its own.

 

[mbender71]

The CCs will not “off gas” as the chlorosulfamate doesn’t leave the water. Every time you add more chlorine, you will create chlorosulfamate from the free sulfamate anion. Over time, the sulfamate anion will hydrolyze into bisulfate and ammonium anions. When that happens, the chlorine will then start to convert the ammonium in nitrate/nitrogen. When that happens, you’ll start to see the pH and TA drop.

I suggest you keep the pH below 8.0. You can target 7.8 and then let it rise from there. You can use the acid demand test if you have it available to determine how much acid to add to get to 7.8. I wouldn’t go any lower because the sulfamate breakdown will eventually start to lower pH on its own.

Howdy! Wow, I'm VERY thankful for the chemistry lesson and the deep insight into my current situation. Thank you! I wish I could say it brought a smile to my face, but it has not. The pool has been down for 3 weeks, and I'm afraid it's going to be many weeks more. I would like to kindly ask the following questions:

1) Should I add muriatic acid to my pool right now based on my electronic pH meter readings?
2) Should I continue the SLAM using TC for FC and monitor CC until below .5?
3) For the OCLT, should I use TC for FC as well or take the FC as a relative value (watching if it goes down more than 1ppm)?
4) Will keeping the pH below 8.0 increase the rate of CC reduction and thus perhaps clearing the pool faster?

Again, thank you SO MUCH for this incredible explanation. I have learned a lot, and hopefully, this thread might help others that go down the sulfamic acid route!

 

[mknauss]

and I'm afraid it's going to be many weeks more.

Earlier, @Mdragger88 suggested a large water exchange to fresh. To rid you of the copper and the issues, consider that.

 

[HermanTX]

I always relied on Pool Math to calculate the amount of 10.5% chlorine given my CYA of 50 (which is FC of 20 ppm). Perhaps I missed that in the SLAM pool school *ugh*.

Pool Math app is just a calculator based on multiple variables. You state "and the pool is between 10k and 12k gallons", therefore depending on which volume you are using, PM will give different results for the amount of PPM increase. Also, depending on how fresh your LC is, that is another variable. So use PM as a guide under normal pool maintenance, but if you are doing a SLAM, then it is best to wait 30mins after adding the LC and test to ensure you reached your SLAM level. Falling short of SLAM level just drags out the process as many members have learned.

Just something for you to consider in the future. Obviously, you have other issues with CC as noted in other discussions, so consider this is for future use. Hopefully you never have to SLAM after you get this cleared up.

 

[JoyfulNoise]

1) Should I add muriatic acid to my pool right now based on my electronic pH meter readings?

Yes. But just enough to lower the pH to 7.8. Don’t go crazy. And make sure your pH meter is properly calibrated.

2) Should I continue the SLAM using TC for FC and monitor CC until below .5?

If your pool needs to be SLAM’d then yes, use TC. With sulfamic acid present you will not be able to add enough liquid chlorine to get the FC high enough. TC is fine. Chlorosulfamate is still a disinfectant, just a cruddy one.

3) For the OCLT, should I use TC for FC as well or take the FC as a relative value (watching if it goes down more than 1ppm)?

I would use TC.

4) Will keeping the pH below 8.0 increase the rate of CC reduction and thus perhaps clearing the pool faster?

Unsure but probably not in a noticeable way. It depends on how pH dependent the formation reactions are for the conversion of sulfamate to chlorosulfamate as well as the hydrolysis of sulfamate into bisulfate and ammonium. My concern about pH is mostly to keep your water from scaling calcium. The breakdown of sulfamate will take time and we haven’t heard about a good way of speeding that up.

 

[mbender71]

Pool Math app is just a calculator based on multiple variables. You state "and the pool is between 10k and 12k gallons", therefore depending on which volume you are using, PM will give different results for the amount of PPM increase. Also, depending on how fresh your LC is, that is another variable. So use PM as a guide under normal pool maintenance, but if you are doing a SLAM, then it is best to wait 30mins after adding the LC and test to ensure you reached your SLAM level. Falling short of SLAM level just drags out the process as many members have learned.

Just something for you to consider in the future. Obviously, you have other issues with CC as noted in other discussions, so consider this is for future use. Hopefully you never have to SLAM after you get this cleared up.

Hello, and thank you for the advice! I will definitely perform an FC test after adding liquid chlorine during my SLAMs from now on. I have been using the TFP method for a couple of months and track how well the additions it recommends (based on my tests) and can safely say the pool is closer to 11k gallons. For this SLAM, I have purchased liquid chlorine from Leslie's in their 2.5-gallon exchange containers. I think it's pretty darn fresh compared to going to Home Depot where the chlorine is old and is stored in the heat so I think I'm on the right track there. I too hope that I will never have to perform a SLAM again! Thank you again

 

[mbender71]

Yes. But just enough to lower the pH to 7.8. Don’t go crazy. And make sure your pH meter is properly calibrated.

Done and thank you! When I took the last pH reading, I checked the meter against my 4, 7, and 10 pH references because I couldn't believe my reading of 9.25 pH in my pool. I'm very confident it's correct soI just added the calculated amount of muriatic acid to bring the pH down to 7.8. I'll let the pool pump mix the water for a couple of hours before I test the pH. I'm going to perform an FC, CC, and pH test right before dark and again before sunrise for an OCLT. I'll make sure to report the findings. I'll be SO happy to not have to count to 120 again

 

[JoyfulNoise]

You can try diluting a water sample or using a 5mL sample so that the conversion is 1ppm/drop. You’re going to burn through a lot of reagent with numbers that high.