I realize this is a question that may yield a subjective answer, but can anyone provide a solid recommendation for a SWG for a 120,000 gallon neighborhood pool. There are a lot of brands and I am looking for some guidance before I start getting quotes.

Thanks in advance.

Here's an objective answer: all of them work the same way and are about equally reliable. The bells and whistles vary a bit between lines and manufacturers, but none are far and away better than any other.

With that size pool you'll need a commercial unit and/or parallel units. Autopilot or Pentair is probably your best bet.

Great info. Thanks much. I am waiting on quotes right now. One of the pool companies we are looking at is really against SWGs. So, at this point, I am on the fence. Cost will be the biggest determining factor as to whether we stay with stick, switch back to liquid or migrate to SWG.

Part of the cost will be installation. Your existing plumbing and equipment configuration will have a lot to do with it.

Do you regularly replace a percentage of pool water?

Do you use ORP?

What are you using today?

Scott

You need to make sure that the system is NSF50 certified, and is sized to meet your local Department of Health Guidelines. Where are you located?

I am in Cobb County GA. The Health Department requires the the free residual chlorine be between 3.0 and 5.0. My understanding is that SWG systems would be hard pressed to achieve that level without supplemental chlorine being added. Especially on a 120,000 gallon pool.

Is that true - or is that anti-salt rhetoric?

Anti-salt rhetoric. An adequately sized system will have no problem maintaining that, with a normal amount of CYA. What does the health department say about CYA levels?

According to Cobb County Health, here are the Pool Chemical requirements

Free Unstabilized Chlorine 1.5ppm - 10ppm, ideal 3.0ppm - 5.0ppm

Free Stabilized Chlorine 3.0ppm - 10.0ppm, ideal 3.0ppm to 5.0ppm

Calcium Hardness 150ppm - 1000ppm, ideal 200ppm - 400ppm

Total Alkalinity 60ppm - 180ppm, ideal 80ppm - 120ppm

Cyanuric Acid 0ppm - 100ppm, ideal 30ppm-50ppm

For a 120000 gallon pool, roughly what would a system consist of, and cost, to be robust enough to provide the proper pool chemistry and be a reliable system for years.

Chill, GA state guidelines call for 3 lbs/10,000 gallons per day. At 120,000 gallons, that would be 36 lbs/day output max.
Cobb County only calls for it to be NSF and to maintain 1-5 ppm, which would depend on your flow rate. At a 6 hr turnover (333 gpm), you need 20 lbs/day output.
This is per the Dept of Environmental Health.
I can check with them again to confirm and verify if you can use a dual system configuration, that is, salt with a bleach or tab back up system. I'll get back with you on this.