Best way to plumb an integrated spa?


Gold Supporter
Aug 28, 2017
Los Altos, CA
Starting a new pool build with an integrated spa. I think the relevant details are: SWG, heater for year-round pool use, 30K gallon pool, 1K gallon spillover spa, two VS pumps. More details can be found in an under construction thread.

The current proposal from the PB is to plumb everything together and have two operating modes, which I believe is pretty typical. Spa mode and pool mode. Spa mode will isolate the spa so that it can be heated. In pool mode the water will be supplied from the pool and returned to the spa and pool causing the spa to overflow.

One potential issue I see with this is the scenario where we have an all day pool party where both pool and spa are used throughout. In this case we would have to be in spa-mode the entire time. Given the use of SWG, I'm wondering if it's reasonable to go for a full day/night without having the SWG or any filtering run on the pool when in spa mode? Doesn't seem Ideal to me, but maybe this is a non-issue.

I of course don't want to go to the other extreme of two completely separate systems with isolated bodies of water, but I assume there are better ways to plumb this type of setup. I'm wondering how others have done it.

What about having things plumbed to be able to run both spa and pool separately at the same time, but then also have a combined mode to mix the water? The heater would be on the spa loop. Not sure about the other equipment. Would you put anything else on the spa loop? Would you duplicate any of the equipment?


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I personally do not see the need for two pumps. Just use an automation system with actuated valves. The very few times you would use the spa for more than an hour you can just add a gallon of bleach in the morning to cover your FC needs for that day. Filtering is not all that necessary every day other than to mix the pool and generate chlorine via your SWCG.

Be sure your SWCG is rated for at least 2X your pool volume. Thus a 60K rated unit.

Take care.


Gold Supporter
Aug 28, 2017
Los Altos, CA
I haven't seen a detailed plumbing schematic yet, so not sure why the PB has two pumps in the proposal. So my thought was we'd end up with two pumps either way, so why not create a second loop that can be used somewhat independently.

On the spa usage, I'm not suggesting the spa will be used continuously for many hours, but rather kids will be going back and forth between pool and spa over the course of many hours. And even if it's sporadic use, I don't want to reheat the spa multiple times during the day/night.

None of this changes your point though, which is to not worry about filtering and just add bleach if needed. But still curious on how others have done it and the reasons why.

Thanks for the feedback..


Well-known member
Jun 23, 2016
Millville, NJ
Mine is plumbed how you describe - two modes (spa & pool). Honestly, last Summer when we had all day gatherings, the spa usually didn’t get turned on until later in the day and getting into the night. I’d just recommend running it a little longer on Monday to make up the chlorine loss or add a jug or two the next day.
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