How many 2" pipes should I bury now?

[SRCal]

Building a new home this summer, will not build pool for a year or more but the decks and retaining walls around the pool area are going in next month. I'd like to bury pipes under the slab now, stub out the PVC in the area where the pool will go, and cap the lines so they're in place when it's time to build the pool.

I have soils analysis and structural engineering in hand so have a good idea of pool construction parameters, but I haven't hired a pool designer yet because it will be at least a year before I can afford to get the pool started. I want to run 2" PVC conduit under the concrete deck now, though; it will be a lot cheaper to complete the trenching before the concrete is poured! Problem is, I don't know how many pipes i need to run, and I'd like to confirm that 2" is the correct size for suction/return lines.

Here are the design parameters:
- pool will be 20' x 30' , shallow end 3' and deep end 7'. Total gallons approximately 21,000 after allowing for steps and 'tanning ledge'.
- negative/vanishing/infinity edge on the 20' (deep) end of the pool; catch basin will hold approximately 800 gallons/100cf of water and will have a separate pump from the primary pool filter pump (I would expect to run one or the other depending on whether the Vanishing Edge effect is being used?)
- poolhouse equipment location is known, and slab will be poured at the same time as the deck; it's 36 feet away - from the center of the nearest edge of the pool (and at the same elevation as the surface of the pool).

Based on the "6 hour rule", I should be circulating about 58gpm from either the catch basin pump or the primary filter pump; I picked 2" pipe because it seems like it meets the maximum 6fps requirement for a 60gpm flow. Is there a a material benefit to stepping up to 2-1/2" suction pipe? The marginal cost isn't much, but I don't want to waste money if it isn't needed.

So - how many pipes do I need, and do they all need to "home run" to the equipment area, or can i combine all the suctions and all the returns into manifolds and only run two pipes for each pump under the concrete?

Has anyone seen a 'pool plumbing for dummies' somewhere on this site, or elsewhere on the web? Apologies for the newbie questions, but I don't know much/anything about pool construction and the concrete trucks aren't all that far away.

Thanks in advance,
SRCal

[PoolDoc]

1. In my area -- Tennessee, Alabama, Georgia -- virtually 100% of the pools over $100,000 (what a pool like your would cost here) have SERIOUS mechanical / structural problems. This includes those built by the 'premier custom pool builder' in Atlanta, now in its 3rd generation of family owners. This generation is adept at marketing, but either lacks the pride or the ability to build a good pool. They LOOK great . . . for 5 years or so. But they have serious operational problems from the get-go.

2. I haven't tracked pool publications intensively for 5 years or so, so it's possible there's something new. But as of 7 years ago, the BEST pool design / repair / operations pools had SERIOUS errors -- in many cases, I have those errors marked with Post-its.

3. California has much stricter structural requirements, so my guess that those problems might be less than they are here. But many of the 'energy-saving' functionally-stupid circulation designs that permeate the industry today originated in California, so I have to suppose they are still present.

4. I've joked, for years, that in the Southeast, commercial engineering firms tend to design 2 or 3 commercial or community pools every decade. The smart ones design 2 per decade. The dumb ones design 3, because it takes them longer to figure out they don't know what the h### they are doing! I used to think it was only a joke. It's not. Most engineering firms lack a clear, practical understanding of how to design a pool. Any concept or method not shared with other, more conventional, construction, they get wrong.

I once watched 3 "top mechanical engineers' parade around a indoor pool, trying to figure out why swimmers were complaining about how cold the air was . . . even though the engineers were dry-skinned in pants and shirts and the swimmers were wet-skinned in suits. In theory they understand the difference between wet-bulb and dry-bulb temps, but it never occurred to them that the swimmers were all 'wet-bulbs' in a room held at 30% relative humidity by their mis-applied and mis-managed "heat recovery system".

5. Pool buyers -- like yourself -- tend to recoil at the idea that a pool they will like in 10 years will cost them perhaps 10% more than a pool they will hate in 2 years. To be fair, I think few pool companies try to SELL superior functional or operational design -- in any case, many companies probably lack the ability to deliver such designs. But if there's no seller 'push' for better functional design, there's no buyer 'pull', either. All the money goes for flash and show . . . and then when the glitz is gone, it's time to sell the property.

6. I can help you. But that help won't be via the forum for the most part, and won't be free. But, you gotta ask yourself: do you want that kind of help? Nothing I could do for you will make a guest, who's walked out onto your pool deck, go "Oh, wow!". It will just help prevent some from saying, under their breath, "Oh, yuck!".

________________________________________

Oh, yeah. To do your pipes right, you pretty much have to design your hydraulic system now. By putting in extra, you can possibly leave yourself some flex room. But without seeing site drawings and layout plans, I can't say how much flex you can leave.

Good luck!

[PoolDoc]

[ Upgraded membership; moved thread to "IG pool" section <= you may need to log out and back in, before you can see everything.

[SRCal]

...100% of the pools over $100,000 (what a pool like your would cost here) have SERIOUS mechanical / structural problems. .... But they have serious operational problems from the get-go.

...SERIOUS errors -- in many cases, I have those errors marked with Post-its.

... California has much stricter structural requirements,

... Most engineering firms lack a clear, practical understanding of how to design a pool. Any concept or method not shared with other, more conventional, construction, they get wrong.

... Pool buyers -- like yourself -- tend to recoil at the idea that a pool they will like in 10 years will cost them perhaps 10% more than a pool they will hate in 2 years. To be fair, I think few pool companies try to SELL superior functional or operational design -- in any case, many companies probably lack the ability to deliver such designs. But if there's no seller 'push' for better functional design, there's no buyer 'pull', either. All the money goes for flash and show . . . and then when the glitz is gone, it's time to sell the property.

Good luck!

If I do a good job, luck will only play a small part in the outcome. it's why I'm asking questions now, instead of after the deck is in place.

When you say 'operational problems' do you mean structural failures? Or design failures like inadequate sizing of catchment basins or aspects of water flow?

I have a lot of questions from your post above, and I imagine some of them should be carried out offline. I will also search the site for answers to questions like, "why would a 20x30 pool with no spa and no retaining walls cost $100K to build?" With regard to structural requirements, the structural engineering was done by a firm that specializes in pool calcs in seismic design areas, and the geotech reports were done by one of the top 2 firms in northern California. The good news is, the soil couldn't be better for a pool: no expansive soils, construction on rock that will support 4000+ psf loads, and no retaining. The only thing that requires some extra work is that the pool site has a 7% pitch and will need a hefty downslope footing. There is, of course, always the potential for differential settlement - I've heard that's a particular challenge with negative edge 'infinity' pools - and I guess I'll have to plan to deal with that later if it occurs in spite of the engineering prescriptions.

I am here to learn how to spend my limited budget wisely, so I don't end up in the "90% of consumers" camp you call out. I don't have any plans to 'bling' this pool; the goal is elegance through simple, clean lines that let the site and the view speak for themselves. My question about pipes is really a generic design concern: I will create a pipe trough on the east and south sides of the pool that let me make changes right up to the time when the pool gets poured, and I may even be able to hold off on the part of the deck that the pipes have to run below. I have seen pictures of pools with dozens of pipes, and others with just a handful, and I would think this one would be on the "fewer" side. But I haven't built a pool before so what do I know?

...I can help you. But that help won't be via the forum for the most part, and won't be free. But, you gotta ask yourself: do you want that kind of help? Nothing I could do for you will make a guest, who's walked out onto your pool deck, go "Oh, wow!". It will just help prevent some from saying, under their breath, "Oh, yuck!".

....Oh, yeah. To do your pipes right, you pretty much have to design your hydraulic system now. By putting in extra, you can possibly leave yourself some flex room. But without seeing site drawings and layout plans, I can't say how much flex you can leave.

I always expect to pay for professional services... and I will definitely be paying for both pool design and mechanical engineering services. When it's time to get serious about building this pool, I'll reach out directly.

[PoolDoc]

When you say 'operational problems' do you mean structural failures? Or design failures like inadequate sizing of catchment basins or aspects of water flow?

All of the above.

1. Expensive pools here go on ridges or mountains. Your costs will be lower, for that aspect.

2. Building a durable zero edge requires a lot more care than I've seen done. But that doesn't mean it's uncommon in your area.

3. Zero edge pools (or any pool with multiple water levels) only work right, if there are no cracks or expansion joint problems. It is possible to build small-ish pools (like yours) as monolithic structures. That tends to eliminate shell cracks and/or joint problems.

4. The other thing with zero edges, is they only work right if the edge is perfectly level (within 1/16" across the length).

5. Most pools crack AND move. Even if you eliminate the cracking, the moving is a problem. Most residential pool guys have a "skimmer" design + experience mindset: Level is within a 1" and it's no problem of the pool moves another 1" in 10 years. Even commercial pool installers, who are building with gutters (1/4" corner to corner) are sloppy. Actually building to maintain 1/16" over a decade is outside the skill set of any builders I've encountered.

6. I've designed, but never had fabricated, an adjustable stainless edge for use on gutters or zero edge pools as a retrofit, or when it's not possible guarantee no settling. (And actually, I'd have to find another fab shop: the foreman I worked with for years died, and his replacement can't touch his skills.) Regardless, it would be preferable to build a fully stable shell if that's possible. I'd guess your seismic guys can tell if if the structure will be stable to 1/16" over a 10 year period.

8. I've never, ever, seen a well designed piping layout -- commercially or residentially, on site or in pictures. The pipe spaghetti you describe is a function of "I don't know how to do it right, so I did it messy."

• Proper pipe design takes into account WHO will be servicing the pool. For example, in my world, I had to consider whether a 5'1" 110lb guard would have to operate a particular valve. Most zero edge piping is too complex for the typical pool guy to really understand . . . and because designs aren't standard (at least here) they can't 'learn them' either.
  
  
• Proper pipe design is at least somewhat intuitive.
  
  
• Proper pipe design avoids things like prime-killing air locked suction bubbles. (Pool builder whine: "The water will be under PRESSURE! Why do I need to worry about grading the pipe!) On many expensive pools it's nearly impossible to prime the pumps.
  
• etc, etc.

9. Pool builders get major financial incentives to stick with a single brand . . . but single brand installs ALWAYS compromise quality. The Hayward SuperPump is an ancient design, that is super reliable and very easy to prime. But the Hayward trichlor feeder is awful. StaRite's entire line is suspect, but their split case DE filter isn't bad. Pentair's saltwater chlorine units are terrible (none of them are great), but their sand filters are possible the simplest and best. And so on.

10. Electronic controls that cannot easily be bypassed are ALWAYS a mistake, as is failing to install redundant lightning protection. (At least, in the East. Not sure about N Calif.)

I will also search the site for answers to questions like, "why would a 20x30 pool with no spa and no retaining walls cost $100K to build?"

That may not be true, there. California, S. Texas, and Florida are the high density pool markets, and have idiosyncratic pricing and designs. Don't assume that I'm correct, but you can be sure you will not find a reliable answer online. Ask locally.

- I've heard that's a particular challenge with negative edge 'infinity' pools - and I guess I'll have to plan to deal with that later if it occurs in spite of the engineering prescriptions.

Plan now.

I am here to learn how to spend my limited budget wisely, so I don't end up in the "90% of consumers" camp you call out. I don't have any plans to 'bling' this pool; the goal is elegance through simple, clean lines that let the site and the view speak for themselves. My question about pipes is really a generic design concern: I will create a pipe trough on the east and south sides of the pool

Have to see some photos of the site, and a site sketch before I can comment beyond what I have!