Not unless you have to shock the pool. Some SWGs can't keep up with the load if an algae bloom gets started and you might have to shock the pool to get rid of it. But under normal circumstances you don't need to add chlorine. You do have to add muriatic acid to bring the PH down about once a week though.

If you keep your pool open over the winter and your water temp falls below 50 degrees +/-, depending on the unit, your SWCG will stop generating and you'll have to add chlorine by another source.

However, once your water temp falls below 50, the chlorine needed isn't much.

Unless you're on some low flow pump such as 2 speed or variable speed, most people do not run them long enough in the summer months here (southwest) to generate enough chlorine. They have two options, pay more for electricity to run the pump or use additional chlorine.

I ran mine for 8 hours per day in Ca. and never had to add additional chlorine except to shock the pool every so often. Most of the SWCG have a "super chlorinate" function on them which is suppose to eliminate the need for external shock but I never found that it could do the job. I went through the winter as well and if it generated less chlorine I never noticed it as there was no swimming going on in the pool and it was so cold that nothing wanted to live in it...in addition, I use to turn the pumps down to 4 hours or so in the winter. The few times I measured chlorine in the winter it wasn't low. In California though, its only below 50 for a few weeks of the year.

I think it really may depend on where you live, the size of your pool and water features. I live in SoFla and have a natural waterfall and a pool that is about 35k gallons. On my pool I add tons of Chlorine during the summer since the SWG cannot create enough chlorine to prevent algae blooms. I have had the company rep come out several times to test the unit and they all say it is working properly.

I am at a point now that I have shut off the SWG and I am hoping with the summer rains that the salt will slowly work its way out of the pool or get to a level that it is insignificant. One very negative aspect of salt I also discovered is that it makes the water extremely toxic to most plants that are near the pool.

kitchenshock - what kind of SWG do you have and do you have a model number for the cell?

I have a zodiac LM40 rated for a 40,000 gal pool. My pool is 33,000 gallons and have no problem keeping the chlorine levels stable. I keep my CYA levels above 60+. I only add liquid chlorine as a boost after a party with a lot of kids. I do run my pump 12h in the summer since I live in Phoenix with temps over 115. My pool is super easy to maintain and love my salt system. Good luck.

tagprod, its an AquaTurbo Cell.

My pool is 28000 gallons and will be getting a Pentair Intellichlor IC-40

We have a larger than average pool, waterfall, negative edge, etc, with a SWG system and we've never added chlorine for the purposes described by others, even during the winter. We add muriatic acid very frequently, but the chlorine level stays generally constant, even with frequent swimmers.

Now, I do add chlorine in very very small quantities, but I do it directly to our sunshelf, it gets algae growing in the grouted areas during high heat in particular. I have found that sprinkling shock directly onto the algae (a few teaspoons, not much) cuts it to nothing. So that's the only chlorine we've had to add, ever.

I have the Aquapure SWG with a 24k gallon pool. I keep the setting at 50%. Is there a rule of thumb around what level to keep this setting at? How do you know if it is enough or not?

Test the water.
I use to keep mine at 5/50% most of the time. Put it closer to 3-4 during the winter and closer to 7 or 8 just before and after a large gathering. Closer to 6 during the absolute heat of the summer with reoccuring heat record days.

We have only done it after pool parties, just a few times. The PB said that it was easier on the cell to do that than to shock the pool using the cell. It's doable, but can wear down your cell faster.

kitchenshock - is the CYA at 80 ppm