Poll and spillover spa - 1 or 2 pumps?

VinceL

LifeTime Supporter
Apr 28, 2012
207
Newton, NC
#1
For starters, I am a complete pool newbie. I have probably spent 30-40 hours over the past couple of weeks reading the TFP forum. I have learned so much and feel very confident about dealing with the PB. :party: So, thank you to all the people on this forum who have posted questions and answers. :cheers:

We are planning to install a fiberglass pool (16' x 37') and a spillover fiberglass spa (8' diameter). We also plan to have the decking plumbed for a possible future waterslide. We plan to go with cartridge filter, SWG, and a Heat Pump.

I have seen plumbing diagrams for using 1 pump for this configuration or using 2 pumps.

I'm looking for advice on which way to go.

With 2 pumps, will I need 2 filters?
With just 1 pump, could people use the spa, swim in the pool, and use the waterslide simultaneously? Or, would 2 pumps be required?
I'm thinking that whether we go with 1 or 2 pumps, both would be 2 speed. Is that the best approach? Our electric rate is relatively low.
What other issues should I be considering as far as deciding which way to go?

Thanks.
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,911
SouthWest Alabama
#2
If you're planning on heating the spa and not the pool but using both (and the slide) I suggest you use 2 pumps. I also suggest you plumb a line from the pool pump to the spa to use for chlorination and you wouldn't have to run the spa pump just to chlorinate the spa. I also wouldn't worry about getting a 2-speed pump for the spa. It's just a little less expense and you'll probably never run the spa pump on low. whereas you'll probably run the pool pump on low most all the time.

You'll also only need one filter.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,181
Pleasanton, CA
#3
There are a couple of different options but in all cases keep in mind that spa jets require high flow rates and you really don't want high flow rates going through filters and heaters because this will cause a reduction in jet performance and it could damage the filter. So if you go with one pump, make sure there is a bypass built in when in spa mode to redirect most of the water around the filter and heater.

With a single pump, it will be dedicated to the spa when using the spa so it won't be available for the slide or any other feature nor filtering the pool. If you want dual use, you have to have dual pumps.

Dual pumps give you much more flexibility but there are several options here as well.

A pump could be used for the spa jets alone which would give you the best jet performance with the smallest pump but the spa will still need a separate return line for heating, filtering and chlorination plus you would need to switch back and forth when heating the spa.

You could put just the heater with the jets so you can heat and use the jets at the same time but then you would want to have a bypass put in for the heater and you wouldn't be able to use the heater for the pool but that may be ok too.

The high end version ($$) would be to have a filter and heater for the spa alone but again, put in a bypass.

These are just some of the options and it really comes down to how you want to use the spa and pool in combination.

But please do not rely upon the design work of your PB when it comes to the spa jets. There are literally dozens of people who post on these forums about weak spa jets and it was due to a bad spa design. As I have mention several times times now, spa jets require high rates which in turn requires large diameter plumbing. So before signing a contract get the details on the spa design and post them back here.
 

VinceL

LifeTime Supporter
Apr 28, 2012
207
Newton, NC
#4
Thanks for the responses.

Your responses have generated some more questions. :?:

1. I am thinking that the bypass has a sensor that detects flow rate and when it exceeds a set value, it diverts the water flow to the bypass. Does it divert all the of the water flow or just the excess flow above the set rate? I am asking because of mas985's comments about using 2 pumps. I would assume that running the spa pump at a high speed for the jets and running the pool pump (either low or high speed?) would exceed the recommended flow rate for the filter/heat pump. So, if all water is diverted to the bypass, then there is no filtering or heating at all. If only some water is diverted, then there would some level of filtering and heating taking place.
2. Do SWG's have a maximum flow rate and thus need a bypass?
3. I assume that you do not want the water feeding the spa jets coming from the SWG....it seems like the chlorine concentration of the water immediately after the SWG would be high enough that getting blasted with that water from the spa jets would be a bit too much. Is my assumption correct?
4. Will the low speed of a pool pump be adequate for filtering the pool and sending water to the water slide? Or does it need to run on high speed?
5. Spa spillover. Under what conditions does the water flow over the spa spillover? Do you shut off the spa drain (or spa pump, if there is one) to create the spillover by having the pool pump return water to the spa? Does low speed on the pool pump provide enough water flow for a reasonable spillover, or do you need to run the pool pump on high speed?

Maybe it would be better if I tried to describe the various ways we think we will want to use the pool and spa. However, never having had a pool or spa, it is difficult to envision the different possible scenarios. So, I am asking these questions (while I am drawing plumbing sketches on a pad of paper), to try to understand the various equipment combinations, capabilities of those combinations, and ultimately costs.

Thanks for your help.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,181
Pleasanton, CA
#5
#1 While that would be nice if it would do that, the bypass will be operated by a valve manually or actuator controlled via a controller. The bypass only bypasses part of the flow so there is enough for filter, heating, chlorinating etc. Basically, the bypass provides an alternate route so that not all of the water has to go through the pad equipment. This lowers head loss and improves flow through the plumbing when running the spa jets. The bypass valve can be adjusted to optimize the flow through the equipment.

#2 SWGs will usually have low head loss so a bypass is not needed but if you have one bypass, you might as well bypass the filter, heater and SWG all in one bypass. Each device does not need its own bypass.

#3 Having the SWG exit the spa jets is not an issue. Many pool/spa combos are plumbed this way. The concentration of the chlorine coming out of the SWG is not all that high.

#4 Circulation yes, but the slide maybe. It depends on the height of the slide and the pump chosen. The maximum head of the pump on low speed determines how high the pump can lift the water on low speed but it also will depend on what else is running at the time that might lower the pressure.

#5 When every you want it to. Some controller do a better job of this than others and have a specific overflow cycle which will run once per day. This is a good idea to keep the spa water chlorinated and fresh. The spillover function works by drawing water from the pool skimmers and main drain and returning to the spa. Spa fills up and overflows back into the pool. Again, if you have a controller, this can be automated.
 

VinceL

LifeTime Supporter
Apr 28, 2012
207
Newton, NC
#6
Thanks for all the answers, Mark.

You've been very helpful, and I think I'm beginning to understand all this pool equipment and plumbing stuff.
 

VinceL

LifeTime Supporter
Apr 28, 2012
207
Newton, NC
#7
Mark, based upon your comments, I have taken a stab at creating a plumbing diagram for our future pool and spa. It's not very pretty, but I think it documents my thinking. I'm sure I have overlooked several things. :?

I would appreciate it if you could take a look and let me know what you think I should change.

[attachment=0:1z9d585k]Pool plumbing diagram.jpg[/attachment:1z9d585k]
 

Attachments

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,181
Pleasanton, CA
#8
Three way valves on actuators can only be set to two positions but any two positions.

What is the elevation of the pool and spa relative to the pumps and are you planning to put the spa pump next to the spa?

Why do you have a check valve on the pool side suction?

With a separate spa pump, you won't need the bypass because you can size your regular pool pump for just the pool, in other words, small.
 

VinceL

LifeTime Supporter
Apr 28, 2012
207
Newton, NC
#9
Thanks for all your help, Mark.

I expect to have a proposal from the PB within the next couple of days. So, I'm trying to understand this stuff so I can talk to him with at least a basic knowledge of pool plumbing.

mas985 said:
Three way valves on actuators can only be set to two positions but any two positions.
So, I guess I'll need some more valves and actuators to have the flexibility to switch to any configuration via automation. Can you use actuators on 2-way valves?

mas985 said:
What is the elevation of the pool and spa relative to the pumps and are you planning to put the spa pump next to the spa?
Spa will be elevated about 16" above pool decking. The equipment pad will be close to the height of the pool decking (maybe as much as 1 foot below)

mas985 said:
Why do you have a check valve on the pool side suction?
I have read about problems with elevated spas draining back into the pool. So, I got paranoid and put check valves on every connection to the spa. :oops: I see now that I don't need one there.

mas985 said:
With a separate spa pump, you won't need the bypass because you can size your regular pool pump for just the pool, in other words, small.
Based on posts that I've read, I'm thinking a 2 speed 3/4 hp pump would be about the right size for the pool. I'm wondering if I should pay a bit extra and put the exact same 2 speed 3/4 hp pump on the spa. That would give me a spare pump on-site.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,181
Pleasanton, CA
#10
Spas with jets require high flows and fairly large pumps so if you had 1-2 jets, a 3/4 HP pump might be big enough. If you want 6 jets, then I would recommend at least 2.5" plumbing and a 1.5 HP full rated pump such as a Whisperflo. I have a whole section on spa pump sizing about half way down through this post:

hydraulics-101-have-you-lost-your-head-t915.html#p6543

The first step is to choose the jets, type and quantity, and then design the plumbing and pump around that.
 

VinceL

LifeTime Supporter
Apr 28, 2012
207
Newton, NC
#12
Yes, the plumbing is finalized. We are about 5 weeks into our installation. All the equipment is on the pad. We have been running the VS pump, filter, SWG for a couple of weeks with the pool. Yesterday, the plumbing for the spa was completed. It is partially filled and we are circulating water through it (to verify no leaks before they finalize the levelling and backfill around it). The pump for the waterslide has been tested, but we have to wait for the decking to be completed before the waterslide can be installed.

We have not yet run the heater (not that we need it in this weather :mrgreen: ). And, we have not been running the acid sense & dispense.

 

XsAllOverIt

LifeTime Supporter
Dec 8, 2010
560
Mount Airy, Maryland
#13
I've got a spa and pool that runs off of the same pump with different valving to run each seperately. I do not divert any water away from the filter and my pump runs 24 hours/day 365 days/year and it's been running for 2 years straight without any issues. I winterize the pool during the winter and keep the spa running full-time.