Low FC SWG running at 100% - replaced cell, same issue

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J

jeffblue

0
Oct 20, 2015
81
Huntington, NY
So i've been having issues with my SWG. Starting off with last year (my first year in this home) everything worked fine. ran swg at around 60% and would maintain 5-7 ppm FC. this year after completing the opening SLAM and passing OCLT i found myself needing to increase the output to 80-90% on 8 hour (11am-5pm, 10pm-12am) to maintain even 5ppm. figured since the cell was probably 6-7 years old (pool was built in 2011) that maybe the cell was shot. i cleaned it with MA as a last ditch effort but it just wasn't producing enough chlorine given the output level. last year if i cranked the cell up after a pool party and ran the pump overnight i'd easily be at 10ppm.

I ended up biting the bullet and purchased a brand new cell (https://www.amazon.com/gp/product/B06XTDJW9N/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1). installed it, and i am having the same symptoms. i decided i'd just set it to 100% and see what happens, ran it that way for 2 full 8 hour cycles and tested it again and had 3ppm chlorine this morning. so basically after 16 hours of run time in 2 days at 100% i'm at 3ppm chlorine which makes no sense. Relevant numbers below. I called hayward and they asked me my phosphate level, which i dont test for, and they claimed that could be whats eating up my chlorine. Could it be that i have some algae and i don't realize it and that's whats eating up my chlorine? I would think even if i had some kind of algae growth, it wouldn't be enough to basically consume the entire amount of chlorine generated by 8 hours a day of 100% cell runtime. i'm at a loss and could really use some advice. Thanks!

FC 3
CC 0
CYA - 75
TA 60
PH 7.2
Borates 50
Salt - 3400
Temp 79
voltage (generating) 23.5
current 5.39
output 100%
Salt 3400
AL - 0
Version 1.58
cell - t15

Power/Generating are both green with no other lights flashing etc. i can hear the relay kick on when it starts generating.
 
I would suggest turning your SWG off, raising your FC levels to 10 at sundown and perform the OCLT test. I think you will need a SLAM, but lest wait for the results.

Felipe
 
Yes, there could be enough algae to consume all the FC a SWG can produce in a day and for the algae not be noticed by eye.

Run an OCLT tonight, keep the pump running overnight with the SWG in the off position.

Phosphates are not consuming the chlorine they are only food for algae. You can search many threads on this subject if you want to.
 
jeffblue said:
So i've been having issues with my SWG. Starting off with last year (my first year in this home) everything worked fine. ran swg at around 60% and would maintain 5-7 ppm FC. this year after completing the opening SLAM and passing OCLT i found myself needing to increase the output to 80-90% on 8 hour (11am-5pm, 10pm-12am) to maintain even 5ppm. figured since the cell was probably 6-7 years old (pool was built in 2011) that maybe the cell was shot. i cleaned it with MA as a last ditch effort but it just wasn't producing enough chlorine given the output level. last year if i cranked the cell up after a pool party and ran the pump overnight i'd easily be at 10ppm.

I ended up biting the bullet and purchased a brand new cell (https://www.amazon.com/gp/product/B06XTDJW9N/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1). installed it, and i am having the same symptoms. i decided i'd just set it to 100% and see what happens, ran it that way for 2 full 8 hour cycles and tested it again and had 3ppm chlorine this morning. so basically after 16 hours of run time in 2 days at 100% i'm at 3ppm chlorine which makes no sense. Relevant numbers below. I called hayward and they asked me my phosphate level, which i dont test for, and they claimed that could be whats eating up my chlorine. Could it be that i have some algae and i don't realize it and that's whats eating up my chlorine? I would think even if i had some kind of algae growth, it wouldn't be enough to basically consume the entire amount of chlorine generated by 8 hours a day of 100% cell runtime. i'm at a loss and could really use some advice. Thanks!

FC 3
CC 0
CYA - 75
TA 60
PH 7.2
Borates 50
Salt - 3400
Temp 79
voltage (generating) 23.5
current 5.39
output 100%
Salt 3400
AL - 0
Version 1.58
cell - t15

Power/Generating are both green with no other lights flashing etc. i can hear the relay kick on when it starts generating.
Click to expand...
Algae most certainly can be consuming the FC as fast as it is being made, and algae spores are microscopic, you can't see them until there are so many that they clump together.

You can always run an Overnight Chlorine Loss Test to see if there are organics at work here.

Your posted FC is below the safe minimum for a CYA of 80ppm (always round up as the test scale is not linear). This will allow any algae spores to get the upper hand quickly, you should immediately supplement with bleach as needed until you figure this out.

BTW- a T-15 cell (40,000 gal) is somewhat small for a 30000 gal pool. We normally recommend a cell that is 2-3 times larger than the pool as the mfg specs are almost always based on running the cell 24/7.

- - - Updated - - -

Man you guys are quick LOL
 
domct203 said:
Algae most certainly can be consuming the FC as fast as it is being made, and algae spores are microscopic, you can't see them until there are so many that they clump together.

You can always run an Overnight Chlorine Loss Test to see if there are organics at work here.

Your posted FC is below the safe minimum for a CYA of 80ppm (always round up as the test scale is not linear). This will allow any algae spores to get the upper hand quickly, you should immediately supplement with bleach as needed until you figure this out.

BTW- a T-15 cell (40,000 gal) is somewhat small for a 30000 gal pool. We normally recommend a cell that is 2-3 times larger than the pool as the mfg specs are almost always based on running the cell 24/7.

- - - Updated - - -

Man you guys are quick LOL
Click to expand...
Thanks for the response. Wow, i did not realize that the t-15 is small for the pool. it seems like that the previous owners could not have done a worse job of purchasing equipment for this pool while still spending a lot of money. 3k on an undersized heat exchanger (that no longer works), oversized single speed pump (2hp), undersized SWG system. i have all their original paperwork. for what they spent they could have gotten a slightly smaller pool, gone solar and variable and had a much longer lasting more effective/efficient setup.

yes this morning it is below the safe minimum so this was the final straw. i added half a gallon of 12% bleach this morning before i left for work.

at this point should i just skip the OCLT and just go straight to starting the SLAM tonight?
 
Run the OCLT and confirm the results. If you want to start the SLAM you can but I'd wait for the OCLT results.

You can get away with that size of cell in New York, but you might need to run the pool a bit longer than a cell that can produce more chlorine. There are only a few options for a larger cell and at that time when the pool was built the Hayward wasn't too bad of an option for your pool in your location.
 

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jeffblue said:
thanks guys, i guess i'll be patient and do the OCLT and then SLAM tomorrow. so if i wanted to pull my pump runtime back to about 6 hours, running it at 100% isn't actually unrealistically high?
Click to expand...
That combination of run time and output would make 1.5ppm of chlorine in your pool. That may or may not work depending on the chlorine demand that your pool has.
 
Update, i did an OCLT and lost >1ppm and the water looked cloudy, then had a bunch of rain the next 2 days and the water was even cloudier, so i did a SLAM and maintained > shock level for 3 days and i passed the OCLT.

the water was crystal clear for several days after as i left the SWG off and the chlorine levels dropped from shock level to about 8-9ppm. turned the generator on for 8 hours a day at 100% and it pretty much maintained the chlorine level at 8ppm with 70-80cya. with the pump running 8 hours with the SWG set at 100% on a brand new cell 3600 ppm salt. the chlorine levels have dropped down to 2-3 over a week. i definitely passed the OCLT and my water was clear to the point of it looking like the pool was empty. I am officially at a loss and very frustrated. my system is basically just not producing chlorine, or at least the amount that it should especially for 8 hours a day at 100%.
 
It appears you are expecting to have a FC loss of less than 2 ppm per day. It is possible, but normally, at the height of the summer, with any amount of bather load, it will be higher than that.

I believe your SWCG is running just fine. You just need to run it longer as it can only produce so much chlorine based on how long you run it.

Good luck.
 
Marty is right on the money. You are only adding 2ppm of FC each day with those settings and your pool needs a bit more than that at this time of year.

Double check the CYA and get it up to 80.

You might think about getting a 2-speed or variable speed pump so you can run longer with less electrical costs.

Another option for 1 or 2 months of the year is to supplement with bleach as needed. This might be your best option for the rest of this swim season.
 
mknauss said:
It appears you are expecting to have a FC loss of less than 2 ppm per day. It is possible, but normally, at the height of the summer, with any amount of bather load, it will be higher than that.

I believe your SWCG is running just fine. You just need to run it longer as it can only produce so much chlorine based on how long you run it.

Good luck.
Click to expand...

ping said:
Marty is right on the money. You are only adding 2ppm of FC each day with those settings and your pool needs a bit more than that at this time of year.

Double check the CYA and get it up to 80.

You might think about getting a 2-speed or variable speed pump so you can run longer with less electrical costs.

Another option for 1 or 2 months of the year is to supplement with bleach as needed. This might be your best option for the rest of this swim season.
Click to expand...

Wow, thanks guys. so its really as simple as that? I will be switching to a variable pump next season anyway as i will most likely be going solar so i'll start looking for one now. now i'm just annoyed at myself that i let it get low enough that i have to SLAM again, but oh well, at least now i know what is going on. man i really wish this pool was smaller sometimes (most of the time). Thanks again!
 
One of the benefits of manually dosing your pool is that you get a 'feel' for the water, you'll quickly recognize the FC demand pattern (and know when something is not right). This is why it is important to know how many ppm of FC your cell is making daily vs test results, and that is where the SWG Runtime Calculator is priceless.

Once my water is in the mid-high 80F's I know my FC usage will be up in the 3ppm range, reaching 4+ppm in mid summer when we are all swimming everyday. That is why I doubled up on my SWG cells, I knew I would need 8-9 hours of cell runtime to make it through summer if only running one cell. Unless the solar is on, I only run my pump 5 hours a day.

IMG_0445.jpg
 

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