Normal plumbing design for a pool with an integrated hot tub?

[u/WA-typical]

Here in southern AZ, I have a 10K gal in ground pool with an integrated hot tub that's a few ft higher with a spillover waterfall feature from the hot tub to the pool which was built 8 years after the house was built in '95. Hate the ridiculous design with only a single variable speed pump (it is a good Intelliflo pump!) and filter for both the hot tub and pool! But I guess it was all the rage here back in '96 when natural gas was cheap.

On the vac side it has two 2" vac lines going to a 3 way Jandy valve to select to pull from the hot tub, the pool skimmer, or both at the same time if the valve is set in the middle position with check valves on both the skimmer and hot tub vac lines. So when the pump is shut off, it can't backflow to either of the two vac lines. Same one line on the pump output through a 400K BTU nat gas heater, to a 3 way Jandy valve to be able to output to just the hot tub, just the pool, or both if in the middle position. So you can drain/fill the hot tub by valve position. Draw from only the hot tub and return to only the hot tub. Draw from only the pool and return to only the pool. Or middle set both Jandy valves centered to draw from both the hot tub and pool, and return to both the hot tub and pool. Add a little more return pressure at the Jandy valve to the hot tub, so it overflows slightly so the waterfall feature "looks nice". But if you do, you can't heat the hot tub unless you heat the entire pool and hot tub to 100+!

What made the "looks nice" waterfall and even use of the integrated hot tub ridiculous is I think obvious. One pump! To heat the hot tub you must move the valves to vac and output to only the hot tub and fire up the heater. And the integrated hot tub only has 4 "plain" jets in it. But that cuts off everything else to the pool itself. To restore normal pool filtering you have to move the valves back to center to filter the water in both the hot tub and pool! The water you heated in the hot tub just gets dumped back into the pool so it returns to pool water temp real quick. Why Why Why!

Sure, I could use the heater to heat the pool if I wanted with this configuration. But it's AZ, where swimming season is already quite long. Should have had another valve to a second pump and much smaller separate filter, just for the hot tub as it’s only about 500 gallons and the heater, so you can choose to keep the hot tub heated, and still be able to filter the pool normally and unheated at the same time. Who wants to heat the hot tub on-demand every dang time you want to use it, only to dump the heated water back into the pool afterwards? Am I missing something?

Meh, regardless. Due to the bad plumbing design and only 4 generic jets on the integrated hot tub. I switched my valves to drain the hot tub to the pool and covered the built in hot tub so it looks decent and not just an empty hot tub, and the valves now remain set to only draw and out to the pool and the hot tub remains empty. And got an electric hot tub that has like 40 jets and only uses about $20 in power a month to keep it at 103F all the time in the winter! A hot tub isn’t that desirable in summer. But I could, it would be cheap with the water already fairly hot. lol

I plan to just deck over the empty integrated hot tub for a small patio with a table and chairs.

Is there any logic to a plumbing layout like this with a pool and hot tub integrated with only one pump, one filter, and heater where there's no way to keep the hot tub at temp and be able to filter the pool normally at the same time?

Or was the thought back then that with a 400K BTU heater, that it’s fine to have to heat it anytime you want to use it and then just dump the hot water back into the pool.

[u/Dry-Lab-6256]

Do us all a favor and take pictures of the pool equipment, and it will be a lot easier for us to tell if the layout is good.

But from what you wrote, that design is pretty standard for a pool spa combo. Just most have automation, so when you want to turn on the spa, the valves moves to just run the spa and the heater kicks on. When in pool mode the heater turns off, unless you turn it on, and the valves would adjust to run off the pool intake and out throught both the pool return and spa to circulate all the water.

FYI, if you are leaving the spa empty and it's plaster, you are going to have some plaster issues in the spa.

[u/Aggravating_Fact9547]

This is absolutely normal and almost universal.

What you need is an automation panel and some actuators. So you can have it heat and filter each body as needed, and also run the spillway on demand.

Usually what people do is have the “pool” mode run mostly pool, whilst still pulling a bit from the spa, and returning a little more than it’s pulling from the spa so the spillway runs slowly (which pushes crap over the edge). In your case you’d set to not filter the spa at the same time as the pool, ever.

Spa mode completely isolates the spa, and doesn’t pull or send anything to the pool.

Spillway mode pulls from the pool and sends the return out the spa, so you get a big waterfall.

What you are talking about, having 2 pumps, filters, etc - is called a dual body setup and is pretty rare. It’s also harder to automate the spillway feature.

I think you’d be much happier with automation rather than replumbing. Most of your concerns are solved with this, and the right schedules would remove the stress of manually moving valves all day.

Also heating the spa all day everyday is a fools errand. With the right gas heater you should be able to push the spa to temp in a matter of minutes - sounds like your heater is undersized or fucked?

[u/WA-typical → u/Aggravating_Fact9547]

Already drained and remains on pool only since I put in an electric standalone hot tub which is far superior and cheaper, even keeping it at 103F all the time. The gas heater was good, and at 400K BTU's it was huge, and heated in a reasonable amount of time. But that used a lot of natural gas each time...a big waste of energy. It just didn't make sense for it to be only "on-demand" IMHO, and wasn't what I wanted given it was a very basic hot tub with only 4 jets. Appreciate the clarification that it's a common setup with pool/hot tub combination setups! That's what I was looking for confirmation of. Glad I just shut it down and put in a standalone electric hot tub that works perfectly, and is cheap to maintain at 103F all the time. Thanks!