AquaPilot SC-48 can't keep up with FC demand

I opened the pool about 2 1/2 weeks ago when the water temp was about 50 F. The water was clear, but just a tad cloudy in the deep end so I shocked and ran the pump 24/7 for the first four days. The water cleared and had a successful overnight FC test (no loss). I then adjusted CYA to about 75. Problem is the SWG cannot seem to keep up with demand. Depending on the day we are losing between 1 to 2 ppm. I'm running the SWG 8 hours at 100% of the highest power level (3) and during these losses I am not running the heater or auto pool cleaner. We have had a ton of pollen so I did another overnight FC test last night and did not lose any FC. Last night there was a trace of CC (less than .5 ppm) but that was gone this morning. In testing FC/CC over the last couple weeks there IS at times CC of .5ppm or less but I figured that might be due to solar cover, pollen etc.

Numbers this morning:
FC: 3.5
CC: 0.0
TC: 3.5
pH: 7.5
T/A: 90
CH: 180
CYA: 75
Salt: 3500 @ SWG unit 3200 w/AquaCheck Strips.
Temp: 78F

Any ideas? Do I need to run the pump/SWG an extra couple hours? In the past we've run 8 hours at 50% of power level 2. This is just the third season for the unit and there is no scale build-up etc. I'm stumped :scratch:
 
Re: SWG can't keep up with FC demand

Hence the "problem" of the SWCG! Sounds like you may need to supplement with bleach.

I'm not gonna lie; I'm not a SWCG fan, and mostly because they are oversold ("Just put this in and set it and forget it. You'll never have to add chlorine again, and it will make all you need"). I've had three different units, and they have all worked. However, I've either had to run the pump longer than normal to keep up production levels or clean the grid plates too often for my liking.

If your pool requires more chlorine than the SWCG can provide, then you will either need to run the pump longer (which will cost you extra electricity) or add liquid. There is nothing wrong with having to add bleach, although it is kind of frustrating after having a SWCG installed and expecting it to keep up with demand!
 
Re: SWG can't keep up with FC demand

A PoolPilot SC48 should be able to keep up with that pool very easily, especially with the water relatively cold. Given that you have already ruled out many of the common causes, there is most likely a problem with the SWG. Could you temporarily put the unit in boost mode, wait five minutes, do a Test PoolPilot, and tell us the amps and volts it reports? After doing that you can turn off boost. Also, do a visual inspection of the cell plates and make sure there isn't any white chalky residue on the plates and no accumulation of any other obvious debris.
 
Re: SWG can't keep up with FC demand

One of the units I ran was the SC60. Great unit when it worked, but too much "down time" for my liking. My pool is roughly the same size as andrewg's, and I run mine for 8 hours a day, every day.

I'm on BBB now, and loving it! I know what is in my pool, because I have added it (via a Liquidator, but I can still see what I have and test/add as needed)! SWCG are great conveniences, but they are not without the constant need of awareness as to if they are producing chlorine or not. Just like anything that is a convenience, they require attention and tweaking. If you like tweaking with stuff (I have no more vehicles with carburetors, for example! I got sick of tweaking them to make things run right!), then a SWCG may be for you! You just have to set your expectations accordingly!
 
Re: SWG can't keep up with FC demand

JasonLion said:
Could you temporarily put the unit in boost mode, wait five minutes, do a Test PoolPilot, and tell us the amps and volts it reports? After doing that you can turn off boost. Also, do a visual inspection of the cell plates and make sure there isn't any white chalky residue on the plates and no accumulation of any other obvious debris.

Thanks Jason. I'll run the test when I'm back home. The plates were clean at start up about 2 1/2 weeks ago. Is this something that could have built up over that time period?

simicrintz said:
There is nothing wrong with having to add bleach, although it is kind of frustrating after having a SWCG installed and expecting it to keep up with demand!
I have always added bleach at times, for shocking or when I knew my settings wouldn't keep up due to bathing load CYA etc, but I hope it doesn't become a daily thing.

I'll run the power test later today.
 
Re: SWG can't keep up with FC demand

29 volts and 6.1 amps suggests that the cell is getting older, running at about 92% of ideal. That fits with this being it's third season, but doesn't really account for what you are seeing.

Is there any chance that your CYA level is actually a fair bit lower than you think it is?
 
Re: SWG can't keep up with FC demand

Well, I always have trouble trusting my eyes with the CYA test, but I'm pretty sure it's between 70 and 80. I had two other people confirm on two different tests. I think I am going to do a reverse-FC hold test tonight, ie run the pump/SWG all night and see what happens. That would probably be a more controlled setting to guage how much chlorine is actually being produced.
 
Andrew, what % are you currently running? When you look at the cell blades, do the two outer blades appear to be shorter than the blades between them? This would appear as if the edges of the outer blades are eroding.
It is possible for the cell to scale up quickly, especially if you've added any alkalinity plus, or calcium chloride or calcium hypochlorite to the pool.

Give it a mild acid wash (4 to 1). Then run a TEST POOL PILOT again.
 
OK, I ran the pump/SWG for 12 hrs from 7pm to 7am @ 100% power setting 3 and the FC went up 1.5ppm (from 5.5 to 7.0)
Poolsean said:
When you look at the cell blades, do the two outer blades appear to be shorter than the blades between them? This would appear as if the edges of the outer blades are eroding. It is possible for the cell to scale up quickly, especially if you've added any alkalinity plus, or calcium chloride or calcium hypochlorite to the pool. Give it a mild acid wash (4 to 1). Then run a TEST POOL PILOT again.
I pulled the cell yesterday afternoon and did notice a very slight hint of erosion on the outer plates, not much at all and I don't think I could quantify it but obviously it was visible to the naked eye. At that time the blades were smooth. I am assuming (maybe incorrectly) that you can you actually see the scale buildup? I'll try to grab some MA today for the wash and I think I will try another overnight FC-hold test as I am not 100% sure this is still not an organic situation.
 

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