Is it normal to have to add liquid chlorine to supplement a SWG?

[har02052]

I have an in ground 25k gallon pool with a vinyl liner and an intellichlor ic40 SWG. We also have an auto cover and always have it covered if we aren't in the pool. The pool company set the SWG at 60%. But after a weekend of having friends over and swimming in the pool, I had zero chlorine in the pool and things turned green. I followed the slam protocol over a few days. I ended up somewhere around 16-20 gallons of 12% chlorine. My cya is 80, pH 7.5, salt 4000ppm. I got the chlorine back into the normal 3-5 range for a few days and it cleared out and looked great. I had set the swg to 80% just because I figured it's a new pool and all our friends keep coming over. A couple days later and there is zero chlorine again. Then repeat this cycle again a few times over the past few weeks. It will especially wipe out the chlorine after rain. But we have had the cover on each time it rains. Is this normal? Is my SWG not working? Or do I just have to keep adding chlorine to keep up?

 

[Newdude]

Overnight Chlorine Loss Test as you may have some residual algae, or new algae.

Then adjust your FC level. I consider low target my min. I consider high target my low target. With a big storm, get together, or particularly high UV day, I fall back into target range and have plenty FC to spare.




Aiming for 3 to 5 is never going to end well, as you've found.

 

[JJ_Tex]

+1 on flirting with the minimums. I too have 70 CYA and I have a panic attack with anything under 5. I sleep so much better when my easy TC test is a nice shade of orange.

 

[HermanTX]

everything that @Newdude said, plus to put it in numbers - if you have a CYA of 80, then you should maintain your FC at 10-12ppm to account for high UV and bather load. Use LC to get the FC up to that level and monitor SWCG to ensure it maintains it at that level.

 

[.ben]

I keep 70-80 CYA in the summer and keep my FC at 7-9. My SWCG is set to generate about 4 ppm daily (40% at 24 hours for my pool) and I make adjustments as necessary. I would be worried if I ever tested as low as 5.

I’ve only added LC once when my pool was brand new 18 months ago. (I ramp up my FC production for a few days prior to adding salt to account for the SWCG being off for 24 hrs after salt addition)

 

[BDY]

Use effects of adding (select “SWG”) in the pool math app to combine your pump run time and SWG % to calculate the FC you are adding

You mentioned SWG % but didn’t mention pump time. How long are you running the pump with the SWG?

 

[DaveTheAccountant]

I have a SWCG and I add a gallon per week.

 

[Mdragger88]

I have a SWCG and I add a gallon per week.

Your swcg is under sized for your pool volume so this is to be expected in the peak of summer as the max your cell can produce in 24hrs is 3.8ppm fc.
The op has a decently sized swcg that can produce up to 6.7ppm/day in his pool - he shouldn’t need to supplement if he’s algae free & has adequate run time/%.

 

[FlappyLipps]

6FC is lava

 

[Mdragger88]

I have an in ground 25k gallon pool with a vinyl liner and an intellichlor ic40 SWG. We also have an auto cover and always have it covered if we aren't in the pool. The pool company set the SWG at 60%. But after a weekend of having friends over and swimming in the pool, I had zero chlorine in the pool and things turned green. I followed the slam protocol over a few days.

The SLAM Process with a green pool generally takes a week or more.

I ended up somewhere around 16-20 gallons of 12% chlorine. My cya is 80, pH 7.5, salt 4000ppm. I got the chlorine back into the normal 3-5 range for a few days and it cleared out and looked great.

This sounds like it wasn’t crystal clear with no algae (dead or alive) before you allowed fc to fall. Also, 3ppm is below minimum.

I had set the swg to 80% just because I figured it's a new pool and all our friends keep coming over. A couple days later and there is zero chlorine again. Then repeat this cycle again a few times over the past few weeks. It will especially wipe out the chlorine after rain. But we have had the cover on each time it rains. Is this normal? Is my SWG not working? Or do I just have to keep adding chlorine to keep up?

You can do an
Overnight Chlorine Loss Test to confirm the suspicion that you aren’t algae free but it sounds like
You need to do the
SLAM Process to the letter:
For a successful SLAM Process
you need to continue to MAINTAIN Slam level fc for your cya as often as possible (multiple times per day is best) until you meet ALL 3 end of slam criteria-

You are done when:

CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
The water is clear.
(Crystal Clear w/no algae dead or alive)

*Check & scrub every nook & cranny where algae may hide (light niches, steps, drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, etc.)
*If water can go there, algae can thrive there.
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.

 

[Bperry]

I have an in ground 25k gallon pool with a vinyl liner and an intellichlor ic40 SWG. We also have an auto cover and always have it covered if we aren't in the pool. The pool company set the SWG at 60%. But after a weekend of having friends over and swimming in the pool, I had zero chlorine in the pool and things turned green. I followed the slam protocol over a few days. I ended up somewhere around 16-20 gallons of 12% chlorine. My cya is 80, pH 7.5, salt 4000ppm. I got the chlorine back into the normal 3-5 range for a few days and it cleared out and looked great. I had set the swg to 80% just because I figured it's a new pool and all our friends keep coming over. A couple days later and there is zero chlorine again. Then repeat this cycle again a few times over the past few weeks. It will especially wipe out the chlorine after rain. But we have had the cover on each time it rains. Is this normal? Is my SWG not working? Or do I just have to keep adding chlorine to keep up?

I see two issues.
1. Sounds like the SLAM process wasn’t finished.
2. 3-5ppm of chlorine is only when there’s low/no CYA in the water. With CYA of 80, you need more chlorine to stay sanitary. You likely still have algae that just isn’t blooming green just yet.

Your SWCG is a little undersized but not too bad. Ideally it should be rated for twice your pool size. So yes, you may need to supplement with liquid.

 

[DaveTheAccountant]

Your swcg is under sized for your pool volume so this is to be expected in the peak of summer as the max your cell can produce in 24hrs is 3.8ppm fc.
The op has a decently sized swcg that can produce up to 6.7ppm/day in his pool - he shouldn’t need to supplement if he’s algae free & has adequate run time/%.

You’re correct.

 

[Mdragger88]

You’re correct.

Not judging- you gotta work with what you got!
I had to dance that dance for many years with various undersized cells- it’s not as bad as having to dose with so much bleach every day but it’s still a pain. My current setup could stand to be larger but it gets the job done. It’s been quite nice to finally just adjust the %/ run time. I actually feel a little neglectful these days

 

[har02052]

Thanks for all your help. I will slam again and do the overnight test.

 

[randytsuch]

Some advice for once you slam, and pass an overnight, and are just using the SWG, and have your FC up where it should be.

I'd measure chlorine every evening for at a while. See if your FC is staying about the same, or if you are losing some each day. Then adjust your SWG percentage based on your readings.
Keep doing daily measurements until FC is pretty constant.

 

[DaveTheAccountant]

Not judging- you gotta work with what you got!
I had to dance that dance for many years with various undersized cells- it’s not as bad as having to dose with so much bleach every day but it’s still a pain. My current setup could stand to be larger but it gets the job done. It’s been quite nice to finally just adjust the %/ run time. I actually feel a little neglectful these days

Believe it or not I only add a gallon per week and maintain 4+ PPM. I run it about 96 hours per week.

 

[STxFarmer]

Have no idea why installers will not oversize the SWG when they do the installation. You can always reduce the output or run the cell for a shorter period of time. But you cannot under any circumstances make that cell produce more than it is designed for. Like for me with 95 degree water temp in my pool Running my IC60 at 60% for 8 hrs/day Normally it is 40% for 6 hours The slight cost difference of the larger cell is well worth the added output And in theory the larger cell will last longer running at a lower output

You put a larger load on the cell than it can handle. But anytime you put a large load on the pool you should add liquid chlorine to boost the levels back up. Seems your cell is running to maintain your pool and that is about it. Every time my kids had a party I always added liquid chlorine after the party, just to maintain with what the cell wasn't keeping up with Bump up your cell production and see where it keeps your FC and leave it a little high

A couple of years ago I found a used IC60 on eBay for $250 and am on my 2nd full year with that cell. My newer IC60 is sitting in the house waiting for the used one to fail.

Salt pools are the best by far in my opinion but they do have their quirks Once you get used to the demand and what to expect you will make the adjustments without really thinking It rains or you have a pool party you need to react Either increase SWG production or add liquid The pool equipment cannot do the thinking for you

Hope all of your friends are enjoying your new pool

 

[Newdude]

Have no idea why installers will not oversize the SWG when they do the installation

Very few fully understand them. Even less care about living with it, so they hook it up and move on. Even LESS care about the pump energy used to run the small SWG and up until somewhat recently, plenty of PBs were still installing energy hog single speed pumps with the 1X SWGs.

 

[DaveTheAccountant]

M

Very few fully understand them. Even less care about living with it, so they hook it up and move on. Even LESS care about the pump energy used to run the small SWG and up until somewhat recently, plenty of PBs were still installing energy hog single speed pumps with the 1X SWGs.

thats exactly my situation.