Owner/Builder needs help, Pool/Spa Water Level, Skimmer install

nyjohnOctober 2, 2009

I'm a rookie owner builder in NY. I'm doing a freeform gunite pool, pretty much using the photos that I've seen from the postings on this forum as a guide. This forum is the best resource I have found, thank you! I (read: my lovely wife) will definitely take a lot of pictures and post them here.

I'm a civil engineer, so I have some knowledge of the various systems, at least in a theoretical sense. I have the permit, and the utilities are marked out. We told all of the neighbors that we are getting a pool, so there's no turning back now! Excavator coming next week. woohoo!

I think I have it 90% figured out. But if someone could lend some knowledge, there are two things I'm unsure of (I'm sure much more to follow):

We are doing a spa, raised 18" or so above the pool, but we don't want a spill-over. I'm undecided on the a separate pump for the spa, but it obviously will use the pool's filtration system. So...How do I keep the water level right in the spa without the benefit of the spillover? In other words, how do I make sure that the pool pump returns exactly the same amount of water to the spa that it took? Do I need to use diverter valves in tandem so that the pool and spa are not circulating water at the same time, and then have a separate pump dedicated for the jets? and if that's the case, do I need 4 suction fittings in the spa, 2 for the jet circuit, and 2 for the filter circuit?

Second question, at the pool skimmer, in front of the weir, there is a trapezoidal channel formed with gunite, and tiled. The top of this space, just below the deck surface, is a very thin amount of gunite. How do they shoot this? Do I need to box this area out with plywood before the gunite guys come?

Actually, one more thing. I want to get the whole thing automated. I was planning on the Intellitouch, and the Intelliflo SVRS pump. I'm still exploring how to control all of this stuff, they must have some type of electrically operated valves, but I have all winter to figure those things out!

Thanks in advance for the input.


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Why don't you want the spa to spill Into the Pool? The Skimmers need to be formed and dug out. They will be completely surrounded by the shot.

    Bookmark   October 2, 2009 at 5:31PM
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Rack Etear

The easiest way to deal with a spa without a spillover is to put an overflow pipe in the spa that runs back to the pool.

Then you will have a small pipe (1/2 typ) that runs between the common line on the filtration system, and the spa return line so that a little bit of pool water floods the spa while in pool mode, and then goes through the overflow pipe. We typically make a small cutout in the tile line that has a pipe at the bottom of it.

I'll try to do an ascii sketch below the O is typically a 2- 2 1/2 pipe that goes back to the pool. This is a top down look the coping would cover the overflow

    Bookmark   October 2, 2009 at 7:03PM
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We just don't want the noise of the spillover. We will have a small water feature on the opposite side of the pool, and that is enough for us.

Overflow pipe, that is really smart. I'll just size that crossover pipe to turn over the spa water at a proportional rate as the pool. Thank you.

I'm not planning on using a skimmer in the spa, and I was going to use 2 main drains, the VGB type with the basin. They seem big, but I don't see another option. Is that typical?

    Bookmark   October 2, 2009 at 9:23PM
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At least 2 2" lines should be used for overflow to the pool. I like to see 3 used for up to 8 foot spas and more if it's larger. Freshly chlorinated must get in the spa. A single 2" line won't do it without the real risk of overflowing. A leaf or two will cause an overflow, Don't put the pool ends too deep in the pool wall. They will need to be blown free of water and sealed for winter.

You cannot balance the suction lines and return lines for two independent bodies of water with one pump. Don't try it. Instead, when the pool is filtering, closing the spa suction and sending some return water to the spa will keep it chlorinated, balanced, and constantly filled with freshly filtered water. Running the spa for 10 minutes a day as part of the filter cycle will help remove any debris that is on the bottom or seating area.

The top of the opening (in the pool) sometimes has a stainless plate set that extends several inches beyond the opening width to provide the added structural rigidity so the top doesn't collapse when some fluffy person stands on coping on top of the mouth of the skimmer.

Properly ordered, the Intellitouch system will come with valve actuators. If additional actuators are needed, they can be ordered and added.


    Bookmark   October 2, 2009 at 9:50PM
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You are creating more chances for problems doing an overflow this way. If you dont like the noise have it spill over at night. It doesnt have to spill long to get the necessary chlorine.
Are you putting a skimmer in the spa?
Yes you will need 2 drains or one trough drain.
If you are adding another pump you will need two more.

Poolguy and Racket:
How do you protect those overflow pipes from being an entrapment hazzard.

    Bookmark   October 3, 2009 at 11:18AM
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A small in-wall skimmer could be used tied into a gravity return to the pool.

    Bookmark   October 3, 2009 at 12:43PM
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I've built maybe a half dozen pools the way you want yours done and did every one the same way Racket described. I used 3 gutter grates and 2" pipes in the spa and returned them to 3 more gutter grates on the tile line at the 3 below on the pool side of the spa wall.
Not very pretty but very functional.

See ya,

    Bookmark   October 3, 2009 at 8:16PM
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A two inch overflow lines will be hard pressed to generate enough suction to be an entrapment hazard, especially since it's the determiner of the water's hight in the spa. The spa's elevation would have to be substantial, say 8 feet above the pool and in a spa fill mode. Spa Fill modes are normally used by service, not homeowners. It would also soon overflow the spa. This is why I like multiple 2 inch overflows. They can usually keep this in check long enough to catch it and correct the valve setting before overflowing.

Once the water reaches the bottom of the overflow pipes in the spa, the water can't get higher. If it does, something is wrong with the spa suction or someone reset the the amount of return water going to the spa when in the filter mode.


    Bookmark   October 3, 2009 at 8:34PM
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This is maybe not something you have thought about.
A open 2" pipe is an entrapment hazard. A small child could get a hand/arm stuck in there and the pipe being partially filled with water could add to it and cause a vacuum when trying to pull it out. There are many documented cases of this happening.
The way it is described by kelly with a grate is safe and the best way to do it.

Not sure how a small skimmer would work. The water would always be at the throat.
You could use a standard skimmer. Put a pipe riser on the second hole to keep the water at the desired level. Only problem is it is only one 2" pipe. Though if it was 2.5 or 3" from the bottom of the skimmer to the pool it move a lot of water and probably not get clogged.

    Bookmark   October 3, 2009 at 9:25PM
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We have done the in wall skimmer before. The return to the spa is throttled down and it is gravity fed back to the pool. its a skimmer. It would have a basket in it that would need to be emptied every now and then.

    Bookmark   October 3, 2009 at 9:38PM
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How to prevent a child's hand from entering? Great point.

A drain cover like those in a portable tub, slightly recessed in the wall works without being obnoxious. Another alternative is a gutter drain with a 4"x6" grate mounted in the wall.

Both have the 2" connection and I can plug it by removing the actual grate from the body to get at the round opening inside. I've seen them in white, gray, and black.

I like racket's idea except winterizing is problematic.

I've seen sceadu's plan in use before but the skimmer needs to be small so as not to be an eyesore and have two 2" lines to go back to the pool or we have an overflow risk.

It's possible that two single skimmer bodies would be needed. Also, since the flow will be low volume, a weir won't help.

There will be gurgling when the spa is not in use and the system is in pool mode, as the water entering the overflow will be dropping straight down about 2 feet. As the water enters the down spout, air will be drawn in. It won't be loud but it will be audible.

How far from the pool will the spa be? These lines from the spa to the pool will need to be pitched slightly downward towards the pool. The pool outlets in the pool will need either drain pots in the wall or the 4"x6" grates also.


    Bookmark   October 4, 2009 at 9:03AM
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Rack Etear

9/10 pools we build are pool/spa combinations we have done it this way for a very long time, and aside of the hypothetical problems it could have, We rarely have problems with it.

One mistake people make it that you need to have some sort of turnover rate on the spa. You have to remember that the water you are returning to the spa is very clean water coming from the pool in most cases. We find the 5-10 GPM is more than an acceptable amount of water being returned to a spa to keep it chemically treated, and clear.

Especially with how little use the hot tubs actually get.

"How far from the pool will the spa be? These lines from the spa to the pool will need to be pitched slightly downward towards the pool. The pool outlets in the pool will need either drain pots in the wall or the 4"x6" grates also. "

Why will they need drain pots? You can use a Sta-rite inlet fitting if you want to protect the line. The pitch isnt that critical as long as its not uphill.

Winterizing is not an issue the line drains itself. If you are in an area where you need to winterize, you just put to outlet of the spa overflow line, at a level close to where the returns are so that you drain the pool down below the overflow line.

    Bookmark   October 4, 2009 at 2:01PM
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Drain pots get covers. It's just so a kid doesn't stick his hand in.

An inlet fitting will reduce the amount of return flow. It could cause a backup to the spa, allowing an overflow.

    Bookmark   October 4, 2009 at 6:19PM
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The top of the skimmer is spanned with the coping stone or deck. I cut an 18"x18" piece of tile to give this upper throat a nice finish.
For your raised spa spill-over, a skimmer works well. The basket picks up any leaves that get in the spa and it makes a clean opening for the spillway. The 2-2" pipes coming from the skimmer and ending in the pool can be covered with a single drain grate. Just remember, the tile in the throat of the skimmer needs to be pitched from the center of the waterline tile in the spa to the bottom of the throat of the skimmer. This maintains the correct water level.

    Bookmark   October 4, 2009 at 11:41PM
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Rack Etear

Why use 2 2" pipes and not 1 2 1/2"? Or 3" the larger pipes are far less likely to clog..

    Bookmark   October 5, 2009 at 12:53AM
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The bigger pipes are too visible and little hands getting stuck are why.


    Bookmark   October 5, 2009 at 6:59AM
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The skimmers I use have 2 2" outlets at the bottom. The basket catches all large debris. The pipes don't get clogged.
IMO and my pools, all pipes entering the pool have an eyeball fitting or a grate. It's the finish look I want.

    Bookmark   October 5, 2009 at 9:50AM
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I really appreciate the discussion, thanks.

Spa plan:

96" round Spa (25 foot circumference)
1000 +/- gallon

Back jet: 1 every 3 feet, 8 total.
Calf Jets: 8
Waterway Poly Storm Jet Bodies. 2" water x 1 1/2 air.

2 plumbing circuits, 2" loops, one for calf, one for back jets

2 1/2" PVC from each loop to pump (each loop will have its own supply)

Aquastar suction outlet/sump, Triple system in floor (200 GPM at 2.8 fps)
Two 3" suction lines to pump(s)

I have two concerns.

(1) Pump size.

Not sure yet. I'm trying to minimize the head loss in the lines, but I don't have a feel for the head/flow at the jets. Is 10 GPM at 20ft of head a good approximation? Help?
I may need two pumps here, one for the calf and one for the back jets. 1 1/2 HP that could bring 10 GPM to each Jet at about 20 feet of head. Does that sound right?

(2) Heater

Tentatively a 400K BTU Pentair. But I'm concerned about the head loss through the heater. Haven't found a curve for this yet. I doubt that I will find a heater that can pass 200 GPM at a low head loss. It is OK to have just one of the loops, say the back jets, go through the heater?

(3) Calf Jets
Should I pair 2 calf jets to each back jet. And make the calf jets minijets?

Any criticism is welcome!


    Bookmark   October 5, 2009 at 12:30PM
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IMO, use the filter pump for filtering, heating, and general ciculation. I would use a separate pump for each set of eight jets. The intellitouch comes with electric valves and will control the heater, jet pumps, lights, etc.
Option: Use the filter pump(4x160) for 4 calf jets(8 seems like a lot) and spa heating and separate pump for the 8 upper jets. In this case the 4x160 gives you a normal filtration speed, a pool cleaner speed, a preferred calf jet speed, and one other calf jet speed.

    Bookmark   October 5, 2009 at 6:06PM
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If you plan on using blowers, use 2, one for the calf jets and one for the upper jets. Trying it with one blower usually results in only one set getting the air.

As Golf says, use two pumps in the spa in his suggested configuration. Reducing the number of jets to 4 will also give you the space you will need for 2 sets of drains.

Make the 4th speed a fast speed for backwashing.


    Bookmark   October 5, 2009 at 8:01PM
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Rack Etear

I have done a ton spa systems lately with waterway jets ( I prefer the standard poly jets over the poly storm).

You can typically do 7-8 waterway jets on a VS pump through the filtration system. I would use a seperate 2hp pump if you want a total of 16 jets. This way you will have multiple levels of jets, especially if you tie the jets together. There is very little to gain by having a variable speed jet pump.

Don't use minijets for calf jets, you will regret it later, you can always turn down the jets if they are too strong using their internal shutoff.

I like to tie the jet lines in with the filtration lines because when running on a low circulation speed, speed for the heater, the jets are less likely to draw in air which cools off the water. If you are not using the jets, you really don't want air drawn into them.

To make all this work, you will have to install a check valve in the spa return line, as well as the jet return line to prevent backwards water flow through the systems.

I would also consider using the waterway channel drains if you have space they are good for 316 gpm @3.9fps It will be easier to install, and will look alot cleaner than 3 individual round grates. There are 3 2 1/2" suctions fittings on the bottom of them which would be perfect for your system.

    Bookmark   October 5, 2009 at 9:29PM
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