Massive Chlorine Consumption Mystery

TulsaPool

Well-known member
Jun 1, 2018
60
Broken Arrow, OK
Good Morning, I've had an ongoing problem with keeping chlorine in the pool for a couple of weeks. It's accelerated the last week or so. Water continues to be clear and no sign of algae. Ive brushed three times a day for the past week and shocked pool twice daily for a week. We had a lot of fourth of July debris basically looks like strips of brown paper enter the pool over the past week and especially the night of the fourth but that is the only abnormal occurrence. The Chlorine issue has actually been a problem for a few days prior to the fourth but not as extreme.

Also strangely ive had to add three bottles of liqid cya in the past month but i lose it quickly. Im leaving cya at 20 while i shock. I add two bottles liquid Cl after Cl falls to around 3 to 5 every 10 hours or so and it typically gets Cl to 15. Phosphates are 0-100. I tested those after someone said that was my issue. Its not and ive had phosphates at 2500 before with no problems. My filter seems to clear out phosphates after a week or so because they always go away.

I also brought tetra test strips at pet store for ammonia and nitrates after reading some of chem geeks post on bacterial cya to ammonia conversion.

I do have nitrates, around 40 ppm as best i can tell. Although the pool store nitrate test shows 3 to 4. I am using tetra strips for aquariums and they are using a pool test brand but I could not find those. No sign of algae so not really concerned about that. I dip ammonia strip for 10 seconds as instructed and initially I see no indication of ammonia. The strip does have tinges of green as it dries but not sure that means anything as it says to compare immediately. Anyone know if this is ok??

I'm thinking I have a bad cell but I have no messages and I see bubbles at returns. Wouldn't bubbles indicate its producing? I grabbed sample from return but got same reading as rest of pool. I took cell off to inspect and it is good condition. I've maintained perfect water chemistry for the most part.

Currently FC swings from 15 down to 3 or so after 10 to 12 hours. I usually shock twice daily to get back to around 15 ppm. I've not had CCs yet. Ive done overnight tests and im losing well over 1 ppm Cl, not really close yet. Salt is now 3700 cause ive added so much liquid chlorine and i will drain and refill some today to lower. TDS is 200, Cya is 30, CH has gone from 200 to around 240 as ive mixed in some calcium hypochlorite shock when I ran out of liquid Cl. TA is 100, ph is kept around 7.6 in between shocks as Cl falls below 10.

Only other thing ive noticed is small white specs in the water and a few larger white chunks on floor. My jets still sputter as they discharge but no one seems concerned as flow/circulation is great. They kind of make a popping noise too. Filter pressure is good and not rising. Im losing my mind and shoulder is killing me from brushing. Also chlorine costs are breaking the bank. Should i just drain this thing or keep at it? Anyone have any ideas or something else to test to see what is causing this?

Last, i am running swg at 100 percent 24 hrs per day. I used to run at 30 percent 12 hours prior to this and maintained around 5 ppm. That's why I thought swg may not be working. The overnight AND daily cl loss has me questioning everything though. Sorry for the long read/post.
 

TulsaPool

Well-known member
Jun 1, 2018
60
Broken Arrow, OK
Your situation sounds like you have organics/algae and you need to follow the SLAM Process.
I am, just seems odd that i have no sign of algae anywhere. Water looks as clear/perfect as possible.
Your situation sounds like you have organics/algae and you need to follow the SLAM Process.
I am, just seems odd that water is pristine, no sign of algae or clarity issues whatsoever.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
29,483
Laughlin, NV
Algae is not green to start. It is in the water. Clarity is in the eye of the beholder. Can you call heads or tails on a quarter in the deep end?
 

mguzzy

Gold Supporter
Jul 8, 2015
1,753
OV, CA
Good Morning, ...

Currently FC swings from 15 down to 3 or so after 10 to 12 hours. I usually shock twice daily to get back to around 15 ppm. I've not had CCs yet. Ive done overnight tests and im losing well over 1 ppm Cl, not really close yet. Salt is now 3700 cause ive added so much liquid chlorine and i will drain and refill some today to lower. TDS is 200, Cya is 30, CH has gone from 200 to around 240 as ive mixed in some calcium hypochlorite shock when I ran out of liquid Cl. TA is 100, ph is kept around 7.6 in between shocks as Cl falls below 10.
...
Based on this chart your CYA looks low for a SWG pool.
Chlorine-CYA-chart
If it is algae that is starting to use your chlorine, it starts like this before it blooms. But first get your CYA up, it may be a chemical process
 

TulsaPool

Well-known member
Jun 1, 2018
60
Broken Arrow, OK
Follow the SLAM Process. A minimum of 30 ppm CYA is recommended. You are not following the process at this time.
I brought CYA up to 50. I actually exchanged salt cell because at this point i dont know what else it could be. I passed the overnight test so its not organics/algae. What is really strange is that even with the new cell at 100 percent it cant keep chlorine over 1 ppm. I also still notice a discharge of many small white flakes in the water beneath surface. I dont see the chlorinator producing bubbles as this occurs, i guess its reversing polarity momentarily or something. I think u mentioned the flakes were from a dirty cell but this is brand new and also the previous cell was actually spotless as well. Any thoughts/ideas?
 

TulsaPool

Well-known member
Jun 1, 2018
60
Broken Arrow, OK
Passing the OCLT is not the first criteria of a successful SLAM. Crystal clear water is. Do you have that?
I dont have it in front of me but i did that earlier today. My readings gave me the potential corrosive message. From latest tests i entered 4 free and total chlorine, salt was 3600, CH was 200, CYA 50, ph 7.4, TA 90.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
29,483
Laughlin, NV
I dont have it in front of me but i did that earlier today. My readings gave me the potential corrosive message. From latest tests i entered 4 free and total chlorine, salt was 3600, CH was 200, CYA 50, ph 7.4, TA 90.
CSI is ~-0.5 as I guessed a water temperature of 85F.

The SWCG can still release some minor calcium even with the CSI at that level. But it will not scale up.

If your unable to hold FC with that SWCG, and the diagnostics from the cell show it is producing chlorine, then the CYA is too low and/or there is organics, of some kind, in the pool water consuming the chlorine.