Plunge/Small Pool/Spa (~1500 gallons) SWG system

ATM

Member
Jun 7, 2024
7
Portland, OR
Pool Size
1600
Hello!
We are currently building a small 1,600 gallon (not 16k!) pool/hot tub (no jets) & trying to decide on a Salt system that works for this "in-between" size where there isn't much info. The husband wants an in-line system (versus drape over). We also plan to use it at varying temps seasonally - pool in the summer & heat to 100+/- in the fall/winter (fingers crossed - having a hard time understanding & getting mixed answers if a heat pump can achieve this in our climate but that's for another thread!). I bring the temp up only because one pool consultant recommended Solaxx's Reliant but they only run in the 50 - 90 degree range so no-go plus they are more expensive than what I think we've landed on. After reading through tons of threads/reviews on TFP, I think we've landed on a CircuPool SWG (Inyo's Pureline was in the running but their 1 year warranty vs CircuPool's 3-5yr was a turn off). I was hoping to be able to use the SJ-20 (on sale & has clear cell housing) but was told we should upgrade to the Universal 25 for the ability to have more fine-tune control since our pool is so small. The UL25 has a dial that lets you set an exact % chlorine output versus the SJ has 4 buttons (the manual doesn't specify but I'm guessing 25 / 50 / 75 / 100%?). My question: Is it reasonable to think we could run the SJ on the lowest (25%?) setting & just adjust our pump run time to get where we need for this little pool... (we are considering CircuPool's Variable Speed pump as well if that matters).

Open to & appreciate suggestions on the above as well as other brands/systems to consider.
Pics attached of the 2 SWG controls (& a rendering of our future dream yard to keep me motivated. Ha!)
Greatly appreciate all the knowledge shared here! Thanks in advance!

CircuPool-SJ_A-Series-Saltwater-Chlorinator-Swimming-Pool-System.jpgCircuPool-Universal40-Saltwater-Chlorinator-Swimming-Pool-System.jpg IMG_4899.JPG
 
Last edited:
Will your spool be covered?

At 25% the SJ20 will generate 1 ppm of FC for every 1.5 hours of pump runtime.
 
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Will your spool be covered?

At 25% the SJ20 will generate 1 ppm of FC for every 1.5 hours of pump runtime.
We do plan to cover it - I want an insulated cover & a lightwieght solar cover. Without having the pool yet, I am assuming in the winter we'll use the insulated cover daily (researching/getting quotes on that now). However, in the summer, I imagine using a light, less cumbersome solar cover daily to reduce debris, while leaving the large, insulated cover off during periods of time we are able to use it frequently (e.g. If I don't expect we'll use the pool for a few days due to life stuff, workload, etc I would put the "big" cover back on?).

The maths! Ahhhh my brain... I'm not quite sure how you got there, but thank you for that! (maybe I figured it out below?)
I haven't delved into the chemistry yet to understand if that is a lot or little daily & to also understand how long to run our pump daily for adequate circulation/skimming. And then calculating for a variable speed pump... (does the VSP matter in the SWG equations?) My brains gonna explode. Ha! o_O

Oooo I JUST came across this calculator while researching your response & got this result (still not sure what our desired daily FC will be/daily loss of FC...)
Screenshot 2024-06-12 at 1.46.07 PM.png

I saw the note in the Pump Runtime blog: "For SWG owners, remember that the SWG % setting will need to change any time you change the pump run time to hit the FC target. Also, as pool temperatures rise, the chlorine extinction increases so not only will SWG % need to increase but pump run time may also need to increase if the setting is already close to, or at, 100%." I understand there will be some adjusting needed seasonally, user load, etc... I just want to make sure we have a SWG that won't overkill our lil' "Spool" while balancing adequate pump run time. Maybe upgrading to the bigger/more expensive unit to be able to have the control of 5-10% is beneficial for our size?? Any help is sooooo verrrrry appreciated. 🙏 (Sorry for the longwinded response - trying to understand gets me all type-y :))
 
With a covered spool you will not have much daily chlorine loss from the suns UV so you will need very little generated from the SWG.

However depending how much and how long you use the spool you will want to run the pump for water circulation maybe more then the SWG needs.

You have a balancing act you will need to figure out.

A SWG that has finer % adjustments gives you more flexibility in balancing between SWG output and pump runtime for different conditions.
 
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