As title states, opened my pool, typical green. Got her running, picked up what I could, tested water, and got to work. I actually had some chlorine, albeit low, and cya was right at about 45. PH slightly low, so got that up to par. Got chlorine up to 7 fairly quick, then worked my way up to slam level (16 for my cya +/-). Checked about 8 hours later, back down to 9. Added again, checked this morning after running all night, back down to 7. Checked pH due to chlorine being below slam, and I’m still at 7.2. Added more chlorine (liquid) and will check later. Is this normal to lose chlorine so fast? I know it’s doing it’s job, as I have cleaned the filter cartridges for seconds time now (lots of congealed junk), and water is clearing nicely. Also added some algae product the pool supply place recommended (copper based). Will continue my testing, vac is just picking up congealed algae now, no more worms or pine needles. Really excited that my cya wasn’t over 100 like the last two seasons due to pool company closing my pool. Anyway, sorry for long read, just wanted to check if falling chlorine from slam is normal this fast.
Disappearing chlorine
- Thread starter Jrock817
- Start date
- Jun 22, 2014
- 47,992
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
You were on the right path until you went to the pool store and did this ....
No copper ever. Plus, algaecides do not kill algae. You need to follow the SLAM Process and stick to only liquid chlorine. Follow that SLAM page carefully and it will work. Just give it some time.
Never mind, I see that it does. Thank you for the link, I just somehow got to the chart for my cya, not that great page that answered my question. Thank you for the quick reply!
- Jun 22, 2014
- 47,992
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Yes, chlorine can drop quite rapidly in the early part of the SLAM. It is key to test a bit more frequently in this early stage and do you best to maintain that elevated FC SLAM level. Eventually it should stabilize.
Saturn94
Bronze Supporter
- Mar 11, 2015
- 1,752
- Pool Size
- 20000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
so I now have 0 cya, and I can’t keep FC levels up. I’m assuming my FC got low enough to allow bacteria to eat cya? Must have happened overnight, such a bummer too. I checked 10 times, everything was going great until last evening, when FC levels were super low, after being at slam level all day. From 16 to no more than 5, no matter how much I added. I did a full test, confirmed cya was just barely at 20, I have strips, confirmed everything and cya was reading less than 30. Only late last night did I even detect CC. Added cya and let pool run. I’m leaving work at noon. I’m assuming bacteria ate my cya, and I may not even have any by the time I get home. Now I have to add all the bleach in America until I kill the bacteria, and break down ammonia? Then I add cya? Or do I try and keep adding it so it helps latch on to chlorine? Never in my life did I think I would ever encounter dropping cya levels lol!
- Jun 22, 2014
- 47,992
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Your signature shows TF-100. Are you saying all of the testing you have been doing to this point is from test strips?
Negative, just had strips in hand to make sure I wasn’t crazy, or that someone didn’t replace my cya reagent with tap water
- Jun 22, 2014
- 47,992
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Okay. It is very odd that you were in a SLAM process yesterday and today all of your levels have dropped just overnight. 
If there was something odd in the water, it should've shown problems as soon as you started adding chemicals. Nevertheless, all you can do now is the following (with lots of chlorine):
1 - Be sure pH is adjusted to about 7.2
2 - Add ONLY liquid chlorine to increase the FC to "10". Let mix in the pool for 10 minutes and test the FC again. No longer than 10 minutes. If the FC fell below 5, increase the FC back to 10 and repeat this test process every 10 minutes until the FC shows signs of holding.
3. Once the FC begins to hold, then you can add stabilizer for a CYA goal of 30.
4. Once the stabilizer is soaking in the water, increase the FC to "12" and contuse the SLAM Process.
Focus on maintaining the FC SLAM level as best as you can, especially during the initial process which seems to be fluctuating so much. If this process doesn't work, it's possible someone added more pool store product than you realize which could've compromised the stability of your TFP water. A large water exchange may be required at that point. Hopefully not, but we'll see.
If there was something odd in the water, it should've shown problems as soon as you started adding chemicals. Nevertheless, all you can do now is the following (with lots of chlorine):1 - Be sure pH is adjusted to about 7.2
2 - Add ONLY liquid chlorine to increase the FC to "10". Let mix in the pool for 10 minutes and test the FC again. No longer than 10 minutes. If the FC fell below 5, increase the FC back to 10 and repeat this test process every 10 minutes until the FC shows signs of holding.
3. Once the FC begins to hold, then you can add stabilizer for a CYA goal of 30.
4. Once the stabilizer is soaking in the water, increase the FC to "12" and contuse the SLAM Process.
Focus on maintaining the FC SLAM level as best as you can, especially during the initial process which seems to be fluctuating so much. If this process doesn't work, it's possible someone added more pool store product than you realize which could've compromised the stability of your TFP water. A large water exchange may be required at that point. Hopefully not, but we'll see.
- Jun 7, 2017
- 9,181
- Pool Size
- 29000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Jandy Aquapure 1400
This sucks for you you'll be clearing the shelves of chlorine. If you have an aquarium ammonia test kit you could use that to track progress neutralizing the ammonia.
I did the big exchange 2 years ago when my cya was over 100 at opening. The FC was waning starting yesterday probably mid day, I was testing and adding, but not rechecking until a few hours later. I assumed once at slam, I’d be ok to check every 2 hours. I was adding based on pool math, but each time test was not where it should be, which prompted the 2 different full tests. I had strips and said, why not try, maybe my tf100 chemicals are all too old. Thanks for the tips, leaving work in a little bit to go buy more stabilizer and all the bleach I can fit in my truck.
If they have an ammonia test I’ll pick one up. At least I am getting the greatest experiences in my first few years. From 100 cya, to broken heater, and now to cya eating bacteria? I’m gonna be a black belt in pool just by getting beat up by other black belts so many times.
I hear that. And thanks again to everyone helping out. Sorry if you live in the northeast, and can’t find liquid chlorine after today.
FC 1
CC 1
pH 7.0 (between 6.8 and 7.2)
TA 50
CYA 30
Added soda to fix pH, then 2 gallons of 10%. That got me to 6FC, 10 minutes later added 2 more. After 10 minutes I was at 14. Checked again, back down to 7. This is wild!
CC 1
pH 7.0 (between 6.8 and 7.2)
TA 50
CYA 30
Added soda to fix pH, then 2 gallons of 10%. That got me to 6FC, 10 minutes later added 2 more. After 10 minutes I was at 14. Checked again, back down to 7. This is wild!
Ok so by fourth addition, went to pick up my child from school. Got back, we are holding at 12 FC and 1CC. I’ll keep checking. Can I accurately test cya at this level of FC? Or is it just pH that is not accurate?
I should also add, I put cya in yesterday, when I first noticed it being low. Probably why I’m at 30 when I got home today
I should also add, I put cya in yesterday, when I first noticed it being low. Probably why I’m at 30 when I got home today
- Jun 7, 2017
- 9,181
- Pool Size
- 29000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Jandy Aquapure 1400
??? You should not add CYA until ALL of the ammonia is gone and the Chlorine holds without disappearing.
This is all new to me. I added it last night before posting this morning. FC is holding at 10, checked three times. Going to check every 30 minutes now. So much chlorine over the past couple days. Recycle went out today, but I think I have added almost 14 gallons at this point. I guess adding multiple times a day did something before I knew what was actually going on. I did not think it would be holding so soon.