use one qt pro algae twice this year total 2 quarts. Today FC: 0.25 CC:0-.25 CYA 35 TA 90 Ph 7.8
UV light rapid free chlorine level dropping
- Thread starter Trader7111
- Start date
Hi trader. Your case seems mysterious to me so it must be driving YOU crazy 
I don't know if my musings will help, but hopefully it will give you some ideas, insights, or things to try.
In my case, I was clearing a swamp where the cya had completely converted to ammonia and was zero. At the time, I was waiting for my test kit and didn't realize I was about to fight ammonia but the water was putrid and black so I started with five gallons of 12% (so about 25 ppm) which didn't make much of a dent. But it was cold, so I wasn't fighting the heat, and over a few days it took me 50+ more gallons. Eventually it held at mustard shock level, where I then kept it. On the first day after I got my kit, I just kept adding and adding until it held. I can't remember precisely how any additions it took, but I "rode" it all day and was also backwashing every hour due to the crazy pressure. I do know I spent the entire weekend monitoring it.
I've read somewhere on this board I believe that there's something like an 8-times multiplier to nail ammonia...but forgive my imprecise recollection. I know that ChemGeek is one poster who would know the formula, so you might want to send him a message. You will do better with a specific target...mine was at the time uninformed
-- One thing that people seem to commonly misunderstand (not saying you're misunderstanding but checking to be certain) is that the most critical part of a SLAM process is the "maintain" the shock level part. By that I mean if someone adds say 20ppm worth of chlorine and then walks away for six hours, and returns to find zero chlorine, they've not "maintained" the shock...the organics have gotten ahead of them and that 20ppm is in essence pretty much "wasted." It really really has to be "maintained" -- otherwise you're just sliding down a hill...
So its entirely possible to have used 100 gallons and not effectively to have "Slammed" a pool, as crazy as that sounds.
The way to make the chlorine work is to not let it drop....you're in a race and can't let it (organics) outpace you. So if one hour later the FC is below our shock target, add to bring it up, over and over again until it holds, using the calculator so you know how many poms precisely you're adding each time.
At this point I think you have a few options...sometimes replacing water is more economical in the end, but I'm not sure if it IS a case of ammonia if that would dilute it enough to make the subsequent slam quicker and easier. Either way, if you have ammonia, you will need to SLAM to prevent ongoing shenanigans like you've experienced
And turning off the UV light would likely help.
Another possible thing clouding the issue here might be your expectation of maintenance levels. To use the TFP method means daily doses of chlorine, and at 30ppm cya, my guess is that depending on your environment, you might easily use 2-3 ppm a day, or half to 3/4 jug of 12% in order to keep your range around 7 and not lower than 4 to be safe.
When you're maintaining like that, ccs aren't usually an issue because you're never dropping below a level where nascent algae is starting.
I hope this helps a little. If I can find the thread about ammonia I'll post a link. Technically, we don't "know" that you have it, but the behavior and comment that you could smell it are clues. You ay want to test specifically for it before proceeding, but suspect you need a full slam either way so maybe it doesn't matter.
- - - Updated - - -
Hi again Trade...here's a blow-by-blow of chemgeek's fight with ammonia
http://www.troublefreepool.com/threads/10519-It-Can-Happen-to-Anyone-Zero-Chlorine-CYA-gt-Ammonia
I don't know if my musings will help, but hopefully it will give you some ideas, insights, or things to try.In my case, I was clearing a swamp where the cya had completely converted to ammonia and was zero. At the time, I was waiting for my test kit and didn't realize I was about to fight ammonia but the water was putrid and black so I started with five gallons of 12% (so about 25 ppm) which didn't make much of a dent. But it was cold, so I wasn't fighting the heat, and over a few days it took me 50+ more gallons. Eventually it held at mustard shock level, where I then kept it. On the first day after I got my kit, I just kept adding and adding until it held. I can't remember precisely how any additions it took, but I "rode" it all day and was also backwashing every hour due to the crazy pressure. I do know I spent the entire weekend monitoring it.
I've read somewhere on this board I believe that there's something like an 8-times multiplier to nail ammonia...but forgive my imprecise recollection. I know that ChemGeek is one poster who would know the formula, so you might want to send him a message. You will do better with a specific target...mine was at the time uninformed
-- One thing that people seem to commonly misunderstand (not saying you're misunderstanding but checking to be certain) is that the most critical part of a SLAM process is the "maintain" the shock level part. By that I mean if someone adds say 20ppm worth of chlorine and then walks away for six hours, and returns to find zero chlorine, they've not "maintained" the shock...the organics have gotten ahead of them and that 20ppm is in essence pretty much "wasted." It really really has to be "maintained" -- otherwise you're just sliding down a hill...
So its entirely possible to have used 100 gallons and not effectively to have "Slammed" a pool, as crazy as that sounds.
The way to make the chlorine work is to not let it drop....you're in a race and can't let it (organics) outpace you. So if one hour later the FC is below our shock target, add to bring it up, over and over again until it holds, using the calculator so you know how many poms precisely you're adding each time.
At this point I think you have a few options...sometimes replacing water is more economical in the end, but I'm not sure if it IS a case of ammonia if that would dilute it enough to make the subsequent slam quicker and easier. Either way, if you have ammonia, you will need to SLAM to prevent ongoing shenanigans like you've experienced
And turning off the UV light would likely help.
Another possible thing clouding the issue here might be your expectation of maintenance levels. To use the TFP method means daily doses of chlorine, and at 30ppm cya, my guess is that depending on your environment, you might easily use 2-3 ppm a day, or half to 3/4 jug of 12% in order to keep your range around 7 and not lower than 4 to be safe.
When you're maintaining like that, ccs aren't usually an issue because you're never dropping below a level where nascent algae is starting.
I hope this helps a little. If I can find the thread about ammonia I'll post a link. Technically, we don't "know" that you have it, but the behavior and comment that you could smell it are clues. You ay want to test specifically for it before proceeding, but suspect you need a full slam either way so maybe it doesn't matter.
- - - Updated - - -
Hi again Trade...here's a blow-by-blow of chemgeek's fight with ammonia
http://www.troublefreepool.com/threads/10519-It-Can-Happen-to-Anyone-Zero-Chlorine-CYA-gt-Ammonia
Welcome Trader,
Where are the above results coming from is you don't mind me asking? The consistent 0.25 reading has me very curious on a couple of levels.
You say 100 Gallons of fresh 12.5% Bleach is what you've consumed. Is that just this summer?
today FC:1 CC:0 TC:1 which is new. UV off/dc. 9pm -1st slam- 20ppm & by 9am loss 19ppm FC but no CC …good 1st time. PH:7.4 CYA: 35 TA:85 will only measure FC every 1 hour to keep >16
Ok, that is a lot of FC/Bleach use. Again, can you please tell me what you are using to measure the FC and other results with?
EDIT:
Sorry, and never mind, I went back through your posts and I assume you are still using the FAS DPD test? A loss of 19 overnight is significant and you should see some CC showing up with that much consumption. I'm sorry, but I am at a loss here.
EDIT:
Sorry, and never mind, I went back through your posts and I assume you are still using the FAS DPD test? A loss of 19 overnight is significant and you should see some CC showing up with that much consumption. I'm sorry, but I am at a loss here.
11:41 am test FC:5 CC:0 1st time that happened good. will add 2 gal bring up to 16ppm
When there is a large drop in CYA over the winter, if the reduction did not come from water dilution and especially if the pool was "let go" so the FC went to zero, then bacteria can convert CYA into ammonia and other partially degraded CYA products as James mentioned. This can create a HUGE chlorine demand. The ammonia will immediately combine with added chlorine to form Combined Chlorine (CC), but it is the easiest to get rid of taking hours to oxidize, though may take a lot of chlorine to do so. It's the partially oxidized CYA products that can take longer, though usually only a few days. This is all described in threads others have referred to including Degradation of Cyanuric Acid (CYA) and It Can Happen to Anyone - Zero Chlorine, CYA-->Ammonia.
If bacteria converted 70 ppm CYA to ammonia, it would produce around 23 ppm ammonia which would take at least 180 ppm FC to get rid of. Sometimes bacteria convert all the way to nitrogen gas in which case one sees CYA loss without the chlorine demand. And, of course, one can have anything in between. It is far easier and better to avoid the problem in the first place by closing the pool as late as possible so that the water is cold, then shock with chlorine and/or add Polyquat algaecide, then open in the spring as early as possible before the water warms up.
If bacteria converted 70 ppm CYA to ammonia, it would produce around 23 ppm ammonia which would take at least 180 ppm FC to get rid of. Sometimes bacteria convert all the way to nitrogen gas in which case one sees CYA loss without the chlorine demand. And, of course, one can have anything in between. It is far easier and better to avoid the problem in the first place by closing the pool as late as possible so that the water is cold, then shock with chlorine and/or add Polyquat algaecide, then open in the spring as early as possible before the water warms up.
is 5ppm in 1:15 acceptable. in the northeast what is the hourly chlorine loss due to the sun?
6:30am test FC:10.5 CC:0.5……so from last test & 30min after last addition of chlorine, the Fc loss 17.5 to 10.5.. OCLT 7ppm in 6 hours, but no increase in CC, so why the FC loss without any real increase in CC?
full test PH:7 TA:90 CYA:50 so my PH fell & CYA increased taking shock level up to 20ppm. any thoughts.
Normally CYA levels do not increase without the addition of something containing cya...nor decrease unless with dilution, or in a rare case, conversion to ammonia. So I'm stumped. You are shocking with liquid chlorine right, and not putting any "powdered shock" in? The latter contains cya.
However, it does sound like our pool is starting to hold on to the chlorine a bit better, so keep at it Maybe the ccs have just oxidized before you read.
However, it does sound like our pool is starting to hold on to the chlorine a bit better, so keep at it
Maybe the ccs have just oxidized before you read.yes swamp woman, it was suggested that i add some cya from 30 to 40-50 range to better hold Fc, so i added it in the beginning via a sock in skimmed… 2 days ago.. just using liquid chlorine(12.5%) also this am found some leaves in skimmer a hand full in each… removed. lets see what happens today. seems like I'm loss in 1ppm per hour…can't be the hand full leaves???
No, shouldn't be just the leaves.
You can lose up to 50% FC from sunlight during daylight hours over time, so the real tale is in your overnight loss from sundown to sunrise. That's why the parameter for slamming is "overnight chlorine les of less than 1."
You can lose up to 50% FC from sunlight during daylight hours over time, so the real tale is in your overnight loss from sundown to sunrise. That's why the parameter for slamming is "overnight chlorine les of less than 1."