cost/benefit shocking pool
- Thread starter iam4iam
- Start date
Well I've been up all night like I predicted. I've been feeding bleach every half-hour or so. I only bought 15x182 oz at Walmart just 2.5 hours ago and I only have 2 left! I just got my first reading where FC was nearly equal to CC (12 min. after adding)! I had 3 measurements in a row around FC=5-6; CC=12-14, all followed by 2x96 more added about 20-30 min. apart! Does it seem reasonable for a semi-clear pool to use $40 worth of bleach in 3 hours on a pool where I could already see the bottom? I could understand and would expect that kind of usage on a '"swamp."
As soon as someone wakes up, let me know what you think. I can't wait for sunlight to see if the pool looks clearer than it did last night. It's tough to just under the artificial light.
As soon as someone wakes up, let me know what you think. I can't wait for sunlight to see if the pool looks clearer than it did last night. It's tough to just under the artificial light.
Just added last 2 jugs of 182 oz after measuring FC=5; CC=11!! $50 worth of bleach in under 3 hours . . . at night??? And I could already see the bottom!! What could I possibly be doing wrong? I don't have this kind of money! I'm just a school teacher (who called in today by the way)! I don't know if I have it in me to suck it up and go by 15 (or 30?) more jugs of 182 oz! It seems insane!)
I do know I need to try CYA test again once the daylight is bright enough. Will the CYA from the 4 lb of dichlor 9 hours ago show up on the test, or will I need to mentally add that to my reading?
I do know I need to try CYA test again once the daylight is bright enough. Will the CYA from the 4 lb of dichlor 9 hours ago show up on the test, or will I need to mentally add that to my reading?
Only 10 minutes after adding last 2 jugs, reading is FC=7.5; CC=9? (I forgot CC # actually, I was so aghast at the FC number! A "net" gain of 2.5 FC for what should have added around 9!) Out of bleach! Also, the water actually looks greener than it did yesterday evening! Could this be because there is now more dead algae in the water? And here comes the sun, and pool store doesn't open until 9:00, and I'm low on CYA. Oh yeah, did I say I was out of bleach? 
6:55am (35 min. after FC=7.5; CC=9?
FC=3.5
CC=7
Is decreasing CC a good sign? Been up all night. Not sure if I can even drive to get more bleach! I know I'm not finished with CC so high, though. It's just costing way to much! (See previous posts.) Besides, fallling asleep at the wheel would be worse than losing some ground on the algae. I guess I should have just cleared the shelves on the last trip!
FC=3.5
CC=7
Is decreasing CC a good sign? Been up all night. Not sure if I can even drive to get more bleach! I know I'm not finished with CC so high, though. It's just costing way to much! (See previous posts.) Besides, fallling asleep at the wheel would be worse than losing some ground on the algae. I guess I should have just cleared the shelves on the last trip!
You're done shocking when:
1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.
I snagged this from Butterfly's sig.
So, I say keep shocking if you have CC of 7. Drive safely!
1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.
I snagged this from Butterfly's sig.
So, I say keep shocking if you have CC of 7. Drive safely!
Yeah, I know the "rules." I just can't help but think something's not right. It's just taking too much bleach. (See swampwoman's post yesterday at 4:41 pm. She turned a swamp into what looks better than mine with 58 gallons = $120. I used 21 gallons in under 3 hours last night and I can't see any difference!
7:35 am:
FC=1.5
CC=5
(Assuming last drop that counts is drop that makes solution stay clear momentarily. Solution always goes back to pink after 15-30 seconds.)
Might as well get the CYA on the same trip as my next wave of bleach. (I can't believe I need more bleach.)
Check that. Might not need CYA. It's sooo hard to measure! Last night I was able to see the dot until the cylinder was full! Sure, I used 4 lbs of dichlor, but even if that does show up already, it should only add about 12ppm. Now I'm getting a reading of around 40-50! So much subjectivity.
FC=1.5
CC=5
(Assuming last drop that counts is drop that makes solution stay clear momentarily. Solution always goes back to pink after 15-30 seconds.)
Might as well get the CYA on the same trip as my next wave of bleach. (I can't believe I need more bleach.)
Check that. Might not need CYA. It's sooo hard to measure! Last night I was able to see the dot until the cylinder was full! Sure, I used 4 lbs of dichlor, but even if that does show up already, it should only add about 12ppm. Now I'm getting a reading of around 40-50! So much subjectivity.
iam4iam said:
It's general knowledge here that CYA doesn't leave your pool except for backwashing, splashout, and draining. However, there are numerous occasions reported by users where the CYA "disappears" over the winter. The theory is that there's bacteria that converts the CYA to ammonia.
This sounds likely in your case. If a pool service was maintaining your pool last year, at CYA reading of 0 makes no sense unless it was all converted. Cleaning up all of that ammonia would absolutely explain your bleach consumption. And your readings indicate progress.
Not actually sure CYA is that low. (See edit to last post.) Either way, wouldn't a ton of ammonia mean the pH would be unusually high? But if my CYA really is 40-50, my shock level (which I couldn't even maintain anyway) was too low all night.
Correct. The solution will go back to pink if you leave it alone, which does not count.iam4iam said:
The breakdown of CYA into ammonia doesn't change the PH significantly. Adding ammonia to the pool would change the PH.
One more trip to Walmart and not going to underguess shock level this time. Put in 6x182 oz. and checked levels 10 min. later:
10:30 am stats:
FC=27
CC=5
First test yet with FC > CC! The true test is how long it lasts during the day. I don't have that much back up bleach. I'll test again at 10:45 and if it has plummeted, my CYA might not be high enough. (I'm still not confident with that test! Could be anywhere from 20-60!)
10:30 am stats:
FC=27
CC=5
First test yet with FC > CC! The true test is how long it lasts during the day. I don't have that much back up bleach. I'll test again at 10:45 and if it has plummeted, my CYA might not be high enough. (I'm still not confident with that test! Could be anywhere from 20-60!)
10:45
FC=18.5
CC=4.5
Since I lost 9 ppm of FC in 15 min. and didn't gain any CC, doesn't that tell me I need more CYA?
FC=18.5
CC=4.5
Since I lost 9 ppm of FC in 15 min. and didn't gain any CC, doesn't that tell me I need more CYA?
11:00
FC=10
CC=3
I'd have to be a fool or a millionaire with no financial concerns to add bleach at this depletion rate.
FC=10
CC=3
I'd have to be a fool or a millionaire with no financial concerns to add bleach at this depletion rate.
Do we get to pick one?
You have no choice other than to let your pool go back green. Besides, I have always heard the more you complain, the longer God let's you live.
You are doing well, FC is higher than CC and the CC level appears to be going down rapidly.
Now that your FC level is more or less holding, shocking only at night is slightly more efficient, less chlorine is lost to sunlight. If I remember your CYA level is around 40, so shocking during the day isn't too bad.
Shock level for a CYA of 40 is 15. (You can go as high as 24 if you want to, but I don't think it will help in this situation).
Now that your FC level is more or less holding, shocking only at night is slightly more efficient, less chlorine is lost to sunlight. If I remember your CYA level is around 40, so shocking during the day isn't too bad.
Shock level for a CYA of 40 is 15. (You can go as high as 24 if you want to, but I don't think it will help in this situation).
11:15
FC=1.5
CC=3.5
The sun's just taking the FC away too fast. (If the FC were doing its job, wouldn't CC have increased during a shock to an FC level of 27?) Indeed, the pool is looking clearer, and I feel like we've come full circle at this point. My original thought which started this topic was whether or not it was worth it to shock during the day, which I understand is mainly a matter of CYA level. (Although it seems everyone was disagreeing with the idea originally, simply telling me to "bring to shock level and MAINTAIN [day or night] until ...")
Bottom line: I think I just threw away $18 by taking FC to 27 during the day.
FC=1.5
CC=3.5
The sun's just taking the FC away too fast. (If the FC were doing its job, wouldn't CC have increased during a shock to an FC level of 27?) Indeed, the pool is looking clearer, and I feel like we've come full circle at this point. My original thought which started this topic was whether or not it was worth it to shock during the day, which I understand is mainly a matter of CYA level. (Although it seems everyone was disagreeing with the idea originally, simply telling me to "bring to shock level and MAINTAIN [day or night] until ...")
Bottom line: I think I just threw away $18 by taking FC to 27 during the day.
Actually, FC decreased way faster than CC during the hour of "the $18 test."
I thought this was what I was proposing to do in the first place (original "cost/benefit" question that started this topic)
I wish I knew what my CYA level is. have no confidence in that test. I only know that CYA>12, since I added 4 lbs of dichlor last night.
Well, if CYA is really zero, or close to zero, then adding chlorine during the day is fine at first, but gets inefficient around now.
When you have ammonia in the water, it reacts with the chlorine very very quickly, faster than sunlight can have any effect. During this phase it is nearly impossible to get any FC reading, as it all breaks down too quickly. However, towards the end of the process, which is where you seem to be, there really isn't any ammonia left and instead you are dealing with partially broken down intermediates which react more slowly. At that point sunlight and CYA become significant contributors to FC loss.
It would be interesting to know how things behave after sunset. That would both give us a better read on how far through the process you are and give a suggestion of what your CYA level might be.
When you have ammonia in the water, it reacts with the chlorine very very quickly, faster than sunlight can have any effect. During this phase it is nearly impossible to get any FC reading, as it all breaks down too quickly. However, towards the end of the process, which is where you seem to be, there really isn't any ammonia left and instead you are dealing with partially broken down intermediates which react more slowly. At that point sunlight and CYA become significant contributors to FC loss.
It would be interesting to know how things behave after sunset. That would both give us a better read on how far through the process you are and give a suggestion of what your CYA level might be.