Intex swg boost mode added too much chlorine

[Stang Guy]

So I just set my 15000 gal max intex swg up. I put it on boost mode overnight. It added too much chlorine. Should I just leave it off until the levels come down to normal? It’s currently @ 12ppm and my cya is about 70ppm.

I bought the over sized swg that’s good up to 15000gal, my pool is only 4400 gal intex 15x48.

Once the levels drop to normal my plans is to keep it on 2-3hrs a day and see how it goes. This is my first time using a swg, I’ve always just used the bleach and 40-50ppm cya method.

 

[Newdude]

Meh. That's not even half SLAM.

Trust me. When you goof with FC, goof on the high side, never the low side. There's leeway above tagert level up to SLAM FC (40% of your CYA, 28 FC for 70) and very little leeway below target level.

There's always some trial and (mostly) error when dialing a new system in. And then trying to repeat it every year thereafter.

 

[generessler]

As @Newdude said, no worries. You're just 2ppm over the target. That's nothing.

We can do some numbers to get you started on a regular schedule. A 15 foot pool with 4 feet of water is ~5,300 gallons. Your swg makes 12 grams / hour. That's 0.53 pounds per day. Your water weighs 44,200 pounds. So the SWG is making 0.53 / 44,200 * 1,000,000 = 12 ppm per day when set at 100%.

This seems to match what you saw when you let it run for most of a day.

June in New York, you'll probably be losing 2-4 ppm per day. That varies wildly with shade, swimmers and other factors. Since you're a little high now, let's call it 2. So I'd start with a setting that's at 2/12 or about one sixth of the cell's capacity. You can get that by running it at 100% for 4 hours a day or at 17% for 24 hours a day or some combination.

At least some TFPers prefer to keep the cell running through most of the daylight hours because that's when the losses are actually happening. One mix that does this is 13 hours at 30%.

Then tweak the schedule to stay in the target range (5-10 for CYA=70). Don't ever stop testing at least a few times a week. Various things demand extra chlorine. You don't ever want to miss them and fall below min.

EDIT: It looks like your pool expects 42" of water rather than 48" assumed above, so it's actually only 4,600 gallons. The cell is making about 14 ppm per day. But all the settings are still fine as a starting point.

 

[Stang Guy]

I thought I read on here that salt pools need 2-4ppm @ 60-80ppm cya? That’s why I thought it was higher than needed. I wasn’t worried about it being too high. So far it only needed 2 hours a day to stay around 12ppm. Once it gets hot and gets more use it’ll need more hours on. Thanks for the math breakdown. Unfortunate there’s no adjustability with this intex swg, it’s 100% all the time.

 

[mgtfp]

For CYA 80, FC 4 is the absolute minimum. You never want to drop below that. To make sure that you never drop below minimum, you target a higher range, about 6-11ppm, so you have wiggle room. Rather err on the high side than the low side. Anything up to SLAM FC is safe to swim in, for CYA 80 that's FC 31ppm.

When shooting above your target range, just turn the SWG down a notch. If it's still rising, turn it down another notch. I wouldn't turn it off, forgetting to turn it back on in time is far worse than overshooting a little.

Edit: And if you can't reduce the output from 100%, then just reduce the runtime a bit. Had missed that last sentence first. And if you can keep it constant at 12ppm with 2 hours runtime, then that's absolutely fine.

 

[mgtfp]

The only advantage of keeping FC below 10 is being able to test pH without having to wait for FC to drop. But there's an easy work around: Just dilute your water sample 1:1 with distilled water (not tap water). That halves the FC in the sample so it doesn't interfere with the pH test, and because distilled water has no TA, it doesn't change the pH of the sample, which is pH buffered due to the TA.

 

[an1vrsy]

Just dilute your water sample 1:1 with distilled water (not tap water)

Good to know. With my pool cover, I end up running around FC 10ppm frequently. That is why I purchased a Apera PH60. Now, I'll just dilute 1:1 my sample with distill water when it happens.

Earlier this month, I was gone for a week, although, I asked my wife to open the cover every day when she got home from work... Well some days she forgot. I got home, tested and it was FC 12ppm, CYA 70. I used the pH drop test with K-2006C anyway knowing pH was going to read high with the drop test. Using the PH60 and knowing my pool, I knew how much MA to dose.

 

[mgtfp]

Good to know. With my pool cover, I end up running around FC 10ppm frequently. That is why I purchased a Apera PH60. Now, I'll just dilute 1:1 my sample with distill water when it happens.

I'm using the PH60 myself, but the dilution trick works just as well. And just for the price of all the calibration solutions you need to keep buying for the meter, you can probably buy a lifetime supply of distilled water.