Hydrotherapy Pool Design Choices

[mareas]

Firstly, thanks for a great community! I have never owned a pool but have been researching for some weeks so excuse me if I come across as ignorant. We are working with a local mennonite pool builder in Mexico but he actually produces fiberglass pools to sell in the USA more than installs them here. We're pushing the limits of his and our own knowledge so I'd like to ask this community on their thoughts.

We are hoping to install a large spa pool for hydrotherapy (10' x 20' x 4.5' fiberglass) which has 14 "seats" that we want to install a mix of venturi and bubbler jets. These pumps will operate on a timer that will turn on the jets for 15 minutes at a time. This requirement as well as our location and the local availability of what manufacturers would consider professionals to install (there are none) mean the usual choices might not be the best recommendation.

For the circulation system I'm looking to install the following in a mechanical room around 30-40 feet away:

RAYPAK ELS-R-0030-3-TI
CircuPool® RJ-20 Salt Chlorine Generator OR EDGE15
CircuPool CC150 Cartridge Filter
CircuPool SmartFlo® Variable Speed Pool Pump - 1.7 THP

However for the jet system I was considering using spa pumps which can be installed closer and below water level such as a 5HP Waterway Viper Spa Pump 2 Spd, 2.5" In-Out or another single speed version. It would be signficantly more cost effective when running between 50-100 spa jets and we would only ever need to run at a single speed for short periods of time when it is turned on. We won't get the better warranty length of a pool pump due to the lack of technicians and I'm unsure if the 15 minute off and on cycles would be suitable for these pumps as well.

While my suggestion is definitely not the norm does it seem reasonable to explore this path further?

 

[ajw22]

Welcome to TFP.

Do you have drawings of the planned pool and equipment plumbing?

14 seats with 50-100 jets is novel.

I hope someone is doing the hydraulics calculations for the plumbing.

 

[mareas]

I suppose that’s my questions importance to me. While I’ve done some basic head calculations using the recommended book I would like to pay an engineer remotely who could design that system fully but working from manufactures parameters vs real life experience can be a big difference.

The numbers do scale quickly. Even a CPM Jet Array would be 56 jets and 980 GPM. I’ve been to spa pools like this in the UK where they have 7-8 jets per seat though and they weren’t new installations (5-10 years old). They were usually set with at least some of the surface above ground which would make sense for spa pumps being used in this implementation

 

[ajw22]

@mas985 can wade in here.

I think you will need multiple pumps depending on the limitations of pipe sizes and the desired jet pressures.

Equipment Pad Best Practices - Further Reading

www.troublefreepool.com

 

[mas985]

Firstly, thanks for a great community! I have never owned a pool but have been researching for some weeks so excuse me if I come across as ignorant. We are working with a local mennonite pool builder in Mexico but he actually produces fiberglass pools to sell in the USA more than installs them here. We're pushing the limits of his and our own knowledge so I'd like to ask this community on their thoughts.

We are hoping to install a large spa pool for hydrotherapy (10' x 20' x 4.5' fiberglass) which has 14 "seats" that we want to install a mix of venturi and bubbler jets.

Will this be an indoor spa (i.e. protected from the elements)?

For the venturi jets, I would assume that you want local air control for each seat?

Where you planning on standard venturi TEES (e.g. #7) or where you looking at Paramount type of jets or jets that typically used in a standalone fiberglass spa?


"Bubbler Jets"? Bubblers are not the same as venturi jets and typically run off of an air blower with no water movement involved and completely separate plumbing from the venturi jets.

For the circulation system I'm looking to install the following in a mechanical room around 30-40 feet away:

RAYPAK ELS-R-0030-3-TI
CircuPool® RJ-20 Salt Chlorine Generator OR EDGE15
CircuPool CC150 Cartridge Filter
CircuPool SmartFlo® Variable Speed Pool Pump - 1.7 THP

This part looks fine as long as you plan on having this on a separate loop with it's own suction and return ports into the spa.

However for the jet system I was considering using spa pumps which can be installed closer and below water level such as a 5HP Waterway Viper Spa Pump 2 Spd, 2.5" In-Out or another single speed version. It would be signficantly more cost effective when running between 50-100 spa jets and we would only ever need to run at a single speed for short periods of time when it is turned on. We won't get the better warranty length of a pool pump due to the lack of technicians and I'm unsure if the 15 minute off and on cycles would be suitable for these pumps as well.

While my suggestion is definitely not the norm does it seem reasonable to explore this path further?

The first thing you should do is identify the jets and configuration for each seat. This is going to dictate the size of the plumbing and the type of pump that is used.

With regards to the Viper, that is a very low head pump and standard spa jets typically used in IG pool/spa combos will have between 50-70 feet of head loss which is outside the operation range of that pump. I believe that pump is designed for a standalone fiberglass spa and the specific jets that are used in those types of spas. So if that is the pump you want to use, you need to design the spa more like a standalone spa and use the appropriate jets.

 

[mareas]

Thanks for such a detailed reply. I'll try group some of the responses to help:

1. Will this be an indoor spa (i.e. protected from the elements)?
It will be outside but we live in a relatively mild area at high altitude (2000m). It's usually warm most days with drops overnight. The pool equipment pad will be within a building and if we use spa pumps they will be installed below frost line closer to the pool with drainage etc.

2. a) For the venturi jets, I would assume that you want local air control for each seat? Where you planning on standard venturi TEES (e.g. #7) or where you looking at Paramount type of jets or jets that typically used in a standalone fiberglass spa?
2. b) The first thing you should do is identify the jets and configuration for each seat. This is going to dictate the size of the plumbing and the type of pump that is used.
I am struggling to make decisions here before deciding how to pump the amount of water required in the non standard way (15 min cycles) and it seems like a chicken and egg situation to me but the pump will probably dictate how many and what type of jets will be used. Its ultimately my complete lack of experience and persons with experience in my area that is leading me to do this in reverse.

3. "Bubbler Jets"? Bubblers are not the same as venturi jets and typically run off of an air blower with no water movement involved and completely separate plumbing from the venturi jets.
I understand but I wanted to mention as we are likely going to use one or more blowers too.

4. This part looks fine as long as you plan on having this on a separate loop with it's own suction and return ports into the spa.
Yes on separate suction and return ports. This was easy thanks to great information in the wikis.

5. With regards to the Viper, that is a very low head pump and standard spa jets typically used in IG pool/spa combos will have between 50-70 feet of head loss which is outside the operation range of that pump. I believe that pump is designed for a standalone fiberglass spa and the specific jets that are used in those types of spas. So if that is the pump you want to use, you need to design the spa more like a standalone spa and use the appropriate jets.

If you excuse my vagueness in response elsewhere this seems like the question in my mind I need to explore further with someone who has the experience. If my very brief understanding of fluid dynamics is right the typically head loss of the IG pool/spa combos would be from distance and turn of pipes, the pump being above the body of water and the type of pump preferred for standard large pools.

1. Would that be the head loss you are pointing out here or does it relate specifically to the type of connections such as fiberglass wall fittings (i.e. Fiberglass Wall Fitting (2" fitting & 3/4 Eye) - CMP) and the air mixers?
2. My way of compensating this is to install the spa pumps within very close proximity to the pool (a few feet) and under the waterline so it performs inline with a hot tub. Would it still be preferred to use manifolds and hot tub fixtures for the jets?

 

[mas985]

Thanks for such a detailed reply. I'll try group some of the responses to help:

1. Will this be an indoor spa (i.e. protected from the elements)?
It will be outside but we live in a relatively mild area at high altitude (2000m). It's usually warm most days with drops overnight. The pool equipment pad will be within a building and if we use spa pumps they will be installed below frost line closer to the pool with drainage etc.

2. a) For the venturi jets, I would assume that you want local air control for each seat? Where you planning on standard venturi TEES (e.g. #7) or where you looking at Paramount type of jets or jets that typically used in a standalone fiberglass spa?
2. b) The first thing you should do is identify the jets and configuration for each seat. This is going to dictate the size of the plumbing and the type of pump that is used.
I am struggling to make decisions here before deciding how to pump the amount of water required in the non standard way (15 min cycles) and it seems like a chicken and egg situation to me but the pump will probably dictate how many and what type of jets will be used. Its ultimately my complete lack of experience and persons with experience in my area that is leading me to do this in reverse.

The pump you picked out is non-starter. I do not know of any spa jets that will work properly with that pump.

3. "Bubbler Jets"? Bubblers are not the same as venturi jets and typically run off of an air blower with no water movement involved and completely separate plumbing from the venturi jets.
I understand but I wanted to mention as we are likely going to use one or more blowers too.

The bubbler blower will need to be dedicated to ONLY the bubblers.

Also, if you plan on having the spa jet pumps close to the jets and the air lines also very close to the jets, you should not need a separate blower for the venturi jets. The venturi will suck in air on their own so the blower is unnecessary and will actually cause too much air in the jet stream.

4. This part looks fine as long as you plan on having this on a separate loop with it's own suction and return ports into the spa.
Yes on separate suction and return ports. This was easy thanks to great information in the wikis.

5. With regards to the Viper, that is a very low head pump and standard spa jets typically used in IG pool/spa combos will have between 50-70 feet of head loss which is outside the operation range of that pump. I believe that pump is designed for a standalone fiberglass spa and the specific jets that are used in those types of spas. So if that is the pump you want to use, you need to design the spa more like a standalone spa and use the appropriate jets.

If you excuse my vagueness in response elsewhere this seems like the question in my mind I need to explore further with someone who has the experience. If my very brief understanding of fluid dynamics is right the typically head loss of the IG pool/spa combos would be from distance and turn of pipes, the pump being above the body of water and the type of pump preferred for standard large pools.

Everything that touches the water will add head loss (e.g. pipes, fittings, valves, filters, heaters, skimmers, main drains, eyeballs, spa jets). But I was not focusing on the circulation loop for the pool, only the spa jet loops and associated pumps. The circulation loop is a low flow rate application so head loss performance is less important where as the spa jet loops are exactly the opposite and too much head loss can reduce performance considerably.

1. Would that be the head loss you are pointing out here or does it relate specifically to the type of connections such as fiberglass wall fittings (i.e. Fiberglass Wall Fitting (2" fitting & 3/4 Eye) - CMP) and the air mixers?

The head loss numbers that I was quoting was for ONLY the spa jets (e.g. venturi tees with nozzles). The other plumbing would add more head loss on top of that.

2. My way of compensating this is to install the spa pumps within very close proximity to the pool (a few feet) and under the waterline so it performs inline with a hot tub. Would it still be preferred to use manifolds and hot tub fixtures for the jets?

Most of the head loss in a properly designed spa is in the spa jets themselves. If properly sized pipe is used to feed those jets, it really doesn't matter that much if the pumps are close or far from the jets. The point of using large pipe in spa plumbing is to make sure the plumbing does not impact performance no matter where the pump is placed.

 

[mas985]

The Executive would be a better choice for a jet pump since it is almost twice the head and would work with most spa jet designs.

https://www.waterwayplastics.com/wp-content/uploads/2015_catalog_pdfs/2015-spa_pumps.pdf

But I believe all of these pumps are designed for applications where the pump is installed in a water-proof housing like a stand-alone spa.