Should I move my SWG?

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billshadow00

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Feb 24, 2018
10
Denver/CO
I bought my house 7 years ago, and it came with my first pool/spa. As an experienced Aerospace Engineer, it has been great fun learning how this stuff works. I am learning that the original builder/installer may not have known their business very well. My spa overflows into the pool. My return plumbing goes: heater -> 3-way variable valve controlling how much flow goes to the pool and spa. From the valve, the pool return flow goes through a Pentair IC40. The spa return goes directly to the spa.

In pool mode, the valve is set to allow some flow to the spa that overflows into the pool, keeping the pool and spa water to similar chemistry. The SWG goes only to the pool, but the spa gets flushed with water from the pool. In the spa mode, the SWG does nothing. In the winter when the pool is closed and the spa is isolated, I have to use manual chemical chlorination.

Reading the Pentair Intellitouch manual, they recommend putting the SWG immediately after the heater (note: I have check valves but skipped over them for clarity), before the 3-way valve so the SWG can service both the pool and spa. Of course, you would need a much lower SWG duty cycle in spa mode than pool mode.

Are there any downsides to the recommended Pentair configuration? It seems better then my current setup - Thoughts? Would you replumb (I'm pretty good with PVC)?

As a side note, thanks to all on this forum for helping me learn over my years of lurking. Just yesterday I noticed that my SWG flow light was green even though the pump was off. I was smart enough to figure I didn't want my SWG trying to make chlorine without any flow. Searching on this forum led me to the advice to another member that the SWG should be wired to the pump relay load so there's no power to it when the pump is not running (thanks Jimrahbe) . Again, the original installers didn't do what the manual says to do - they wired it so that it was powered on all the time, relying on the flow switch to prevent a big problem (what I would call a single point failure). I'm not sure how long the flow switch has been faulty, but hopefully it didn't do too much damage. It is now wired to the pump relay as I await my replacement flow switch.

Bill
 
Bill,

Since you have the IntelliTouch, it only makes sense to have the SWCG plumbed to both the pool and spa.. I would replumb it..

The Automation will change the % of output when you go into the spa mode.. You can set the % of output individually for the Pool and the Spa.

I am not a fan of constantly running spillovers.. You can, if you want, set up the "spillway" mode so that the overflow only works a couple of times a day to keep the spa water fresh.

Good job on correcting the single point of failure SWCG wiring problem. :thumleft:

Thanks,

Jim R.
 
Thanks, Jim!

What are your objections to spillovers? Before you answer, perhaps I should clarify my situation in case I'm misusing the word, "spillover":

My "spillover" is not like a waterfall. My spa is partially elevated about 2 ft above my in-ground pool, and at the spa waterline there are two 2" round openings with PVC embedded in the concrete wall between the spa and pool. The spa overflow drains into these PVC conduits, which go straight down and discharge from the pool wall into the pool about 2 ft below the pool waterline. In pool mode, a relatively small flow goes into the spa, and slowly overflows into the pool through these two PVC conduits.

On occasion, my spa will start to feel a little slimy and cloudy while the pool looks fine. I suspect the small diverted flow from the pool to the spa may not always be sufficient to keep the spa sanitizer high enough (or I have allowed the pool sanitizer level to drop to low and the spa shows the first signs of it). I have confirmed this by testing the pool and spa separately and the spa generally has less sanitizer. I've been meaning to make some measurements of the turnover rate in the spa from the diverted return flow in pool mode, but haven't got around to it. Any idea what turnover rate I should target? Or, a better question given I don't run my pumps all day (8-10 hours/day), is how may spa turnovers per day should I target in pool mode? I have played with the valve stop position to try and increase the turnover slightly, but I was shy about overwhelming those 2 waterline drains in the spa - there's room to increase it because the spa level never goes above about 1/3rd of the way above the bottom of the 2" round waterline openings. Of course, this would go away if I replumb the system to utilize the SWG for both pool and spa.

Thanks for any thoughts.

Bill
 
mguzzy said:
Sounds like you need to readjust your system to let more water through the spa and just deal with potential increase in pH. Or routinely flush the water from the spa into the pool and back again. I do this once a week or so.
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I tested my spa and pool. Pool FC=6.0 and spa FC=5.6. To me that means the mixing of the spa is OK. I think that if my FC gets low, my spa will start showing symptoms before the pool.
 
Yeah that seems close enough that you'll never really notice the difference. I have my SWG in the piping before the valve that splits the spa and pool returns so the spa and pool get the same Cl, but I manage the flow to each by the position of the valves. What I have found is the spa is a smaller body of water, but its gets used with a higher concentration of bathers and at higher temps. Both of which will create larger Cl demand. But it doesn't get used long enough to really make a difference and I am back to flushing water through the spa. It sounds like you get enough flush from the pool to chlorinate the spa, so is it worth it to replump the whole thing.. probably not.
 
Thanks, mguzzy! I am leaning toward the same conclusion as you... not worth replumbing right now. As I contemplated replumbing, it did occur to me that I may be trading one challenge with another: trying to find the right balance of chlorination between spa and pool. On the other hand, I close my pool in the winter and keep the spa open, and have to manually treat the spa, so having the chlorinator flow to the spa would be helpful in the winter. More to think about... thanks again.
 
billshadow00 said:
On the other hand, I close my pool in the winter and keep the spa open, and have to manually treat the spa, so having the chlorinator flow to the spa would be helpful in the winter. More to think about... thanks again.
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Well that would make it worth it to use the SWG in the winter for sure.. but I would do it really only if there was another compelling reason to start hacksawing your PVC ;) It probably doesn't take that much CL to keep things happy in the Spa in the off season.
 
The SWG stops working at around 55 degrees and you have to chlorinate by other means. I'm sure one of the experts will expand on that and with the exact temp. I believe it is in the SWG manual. I had a house with SWG many years ago and poured bleach in every winter. I now have a new pool that I know I will have to do the same in the winter.
 

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