Help with Spa design

[kapooramit7]

Hello All,

We are building a 16 X 28 pool with 6 X 6 Spa tucked in a corner. PB proposed 4 waterway spa jets (each 10 GMP) with one common pump (Jandy VS-E-Pump 2.7HP), heater, and filter for both pool & spa.
I understand there are limitations to the true spa experience one could achieve with a gunite spa. Still, trying to get at least one (preferably two) seats in my Spa to have decent therapeutic experience.

Below is a diagram of the slightly modified design I came up with (largely thanks to information collected via this forum). Would love to hear answers/feedback on the following

1. With bigger jets, spa would require ~60 GPM (compared to ~40 GMP in original design). I am asking PB to use 3" for both suction & return and also get a bigger pump VS 3.7 HP, hoping with those upgrades system will be sufficiently powered? Can I even go a little higher (70-80 GPM) and add one jet to the Seat D? Please note that jets won't be plumbed directly to the pump so we need to consider flow restrictions of heater & filter too.

2. Would different sizes of jet on each side 20 GPM (Seat A), 10 GPM (Seat B), 30 GPM (Seat C), 0 GPM (Seat D) create any sort of issues with water flowing in at different rates (they will all be plumbed on a single loop).

 

[ajw22]

Why not have a dedicated spa pump?

A second pump adds little to the overall cost of your build.

This is my spa…

Equipment Pad Best Practices - Further Reading

www.troublefreepool.com

Gunite Spas - Further Reading

www.troublefreepool.com

 

[kapooramit7]

Thanks @ajw22
Are the returns on lower level of your spa (which bring in heated + filtered water) also jets or are they simple returns?

I can go with a separate spa pump too (plumbed directly to the jets without heater+filter), but have the following concern with that set-up.

In SPA only mode, the spa pump will be powering the jets, but the main pump will still need to operational and bring in some filtered+heated water, right?

My PB mentioned that heater needs to maintain a minimum GPM of 40 otherwise it makes a lot of noise, which means we would need to connect 3-4 jets to the main pump anyway and the spa/booster pump would cover the remaining. This seems like an overkill for the rather small spa unless I add more jets and maybe divide it as a ~40 GPM via main pump & 70-80 GPM via spa pump (directly). Do you ever run your spa only on the spa pump? maybe after the water is already filtered & heated via main pump? If you always operate them together, do you reduce the flow of returns/jets from the main pump?

"Would different sizes of jet on each side 20 GPM (Seat A), 10 GPM (Seat B), 30 GPM (Seat C), 0 GPM (Seat D) create any sort of issues with water flowing in at different rates (they will all be plumbed on a single loop)." - curious to hear your opinion on this.

 

[ajw22]

Thanks @ajw22
Are the returns on lower level of your spa (which bring in heated + filtered water) also jets or are they simple returns?

Just returns to heat, chlorinate, and filter the spa water.

In SPA only mode, the spa pump will be powering the jets, but the main pump will still need to operational and bring in some filtered+heated water, right?

Yes. So when you want to filter and heat the spa it is in SPA mode.

Sometimes we enjoy a nice soak and don’t run the spa jets.

You have more flexibility in using the spa without needing to run the jets.

My PB mentioned that heater needs to maintain a minimum GPM of 40 otherwise it makes a lot of noise,

has heaters require a minimum of 40 GPM. I run about 50 GPM.

Noise where? It creates no noise at the spa.

which means we would need to connect 3-4 jets to the main pump anyway and the spa/booster pump would cover the remaining.

Why? No reason to do that.

This seems like an overkill for the rather small spa unless I add more jets and maybe divide it as a ~40 GPM via main pump & 70-80 GPM via spa pump (directly).

This makes no sense. You are overthinking.

Do you ever run your spa only on the spa pump?

why? What benefit is there to do that?

As I said above I will run the spa with only the filter pump. Then turn on jets or air blower or both depending on mood.

maybe after the water is already filtered & heated via main pump?

Why?

If you always operate them together, do you reduce the flow of returns/jets from the main pump?

IntelliCenter sets pump speed for 20-25 GPM when no heat and 50 GPM when heater is on.

"Would different sizes of jet on each side 20 GPM (Seat A), 10 GPM (Seat B), 30 GPM (Seat C), 0 GPM (Seat D) create any sort of issues with water flowing in at different rates (they will all be plumbed on a single loop)." - curious to hear your opinion on this.

Bernoullis Law.

The flow will be the same to all jets. Pressure will vary with orifice size.

You feel pressure more than flow.