I think you have a math error.

First, figure with head loss, 100 GPM per at max speed. That 6000 GPH per pump or 12,000 per hour. 5-1/2 hour turnover. Drop them down to 33 GPM each for a 16 1/2 hour turn. Heater and salt cell work fine. Power consumption will be about 500 watts per pump, where they are the much more efficient.

Never figure velocity for a return or suction at more than 7 fps. This equate to a 70 gpm flow for a single 2", Friction head loss increases very quickly after that.

A 2-1/2 At 7 fps will send 160 gpm.

Scott

If you are interested in efficiency...

I would recommend using Clean and Clear Plus cartridge filters instead of sand. My IntelliFlo VF was drawing about 1000 watts at 35GPM through my sand filter. When I changed to the quad cartridge Clean and Clear Plus filter (CCP420), it dropped to 620 watts at 35GPM. However, for your pool, I would go with the CCP520 model.

Or a Quad DE. Both are similar in terms of flow efficiency but the Quad DE filters smaller stuff so when the lights are turned on, the water is visibly clearer.

Scott

I disagree with both Landa and Scott.

I also have a very large pool (120,000 gallons).

IMO, you should use a minimum of 2 60 sq/ft DE filters or preferably 2 72 sq/ft DE filters.
Larger bodies of water (over 50,000 gallons) will not appear as crystal clear utilizing high surface area multi-cartridge or high capacity sand filters. They don't pick up the smaller particulate that a DE filter will capture.
If using a sand filter is your objective use 2 TR 140 C3 sand filters. If using a multi-cartridge filter is your objective use 2 500 sq/ft or larger filters.
On my pool I use 3 60 sq/ft DE filters and 15 returns with 3/4 openings. They move a lot of water with a minimum velocity.

More than anything else on your pool the avenue of suction is of the utmost importance. You cant discharge what your unable to suck from the pool.
If using the variable speed pumps at low RPM you should definitely put in a third Intelliflo pump or be prepared to run 24/7 on the 2 pumps you already specified. My guess would be 2 intelliflo's on a lower speed would turn about 100,000 gallons daily on 24/7 circulation. 3 Intelliflows at 16 hours should deliver about the same.
I'm not big on all the arithmetic many people use, I've always done my math rounded in my head. 2 pumps at 35 GPM = 4200 GPH. Rounded to 4000 GPH times 24 hours rounded to 25 hours equals 100,000. I guess I'm really old school in my stuff.
But, I promise you this, at 49 with 30+ building pools for others first and then myself I know what does and doesn't work in the real world.
If I were building your pool in my backyard I'd use 2 at 24/7 or 3 at 16 hours.

I hope this helps.

See ya,
Kelly

Kelly,

Where do we disagree? The QuadDE is a DE filter.

They only have 67,000 gallons.

At 33 gpm times 2 pumps = 66 gpm times 60 min./hour = 3960 gph times 16.5 hours = 65,340 gallons.

Maybe bumping up to 40 gpm would be better for the pool. At 14 hours, it's 76,800 gallons per daily cycle.

I assumed 2 filters, not one.

Hugs!

Scott

I was assuming a design criteria of sub-6-hour turn-over; running a 4 inch return line in a loop around the pool for equalized pressure between the return heads. 4 inch schedule 40 pipe @ 240 gpm is right at 6 FPS. With 67K gallons, this provides for a complete turn-over of 4 hours 40 minutes.
Is there any consolidated list of equipment, pipe & pipe fitting feet-of-head values that would help calculate total head loss? The Intelliflow performance chart appears to show that I can achieve 120 GPM per pump with up to about 75 feet of head, or 150 GPM per pump with 50 feet of head. In Houston, it is as flat as a pancake, and the only topography on my lot is the drainage grading, so I'm assuming the total head is going to come from piping, fittings and equipment.
My goal with regards to the number of return jets is to not create too much back pressure on the pump by having too few returns. How many gallons per minute can one put through a 3/4" return nozzle before it creates significant pressure increase in the return line?
[IMG]http://i31.tinypic.com/282gl1u.jpg[/IMG]

Here is a link that might be useful:

If you are going to have two pumps and two filters, why not run them on separate lines? You will have much better performance if you use more smaller pipe than a single large pipe. When running parallel pumps into the same pipe, both pumps see the total head loss due to the flow rates combined so each pump will have less flow rate than if run on separate lines. For example here are a couple of scenarios to consider.

First assume 40' runs and each pump has it's own 2.5" pad plumbing and filter. No heater and a few valves each. First Intelliflo at full speed.

Scenario #1
Single 4" suction and return lines.
Each pump would experience 56' of head and deliver 140 GPM.

Scenario #2
Dual 3" suction and return lines (one for each pump)
Each pump would experience 54' of head and deliver 143 GPM.

Scenario #3
Quad 2.5" suction and return lines (two for each pump)
Each pump would experience 50' of head and deliver 151 GPM.

BTW, most of the head loss in each of these cases is in the pad plumbing but it would be a real pain to increase the size of the pad plumbing and probably wouldn't help much because of the filter and the many reducers required.

Also, there is probably no reason to run at full speed but it shows the difference in performance and clearly #3 is the winner.

With a 67k gallon pool, you will probably only need 3 turnovers per day at most which is about 140 GPM or 70 GPM per pump. Each of the three scenarios above can do that but will require slightly different energy to do so.

Assuming 24/7 operation at 70 GPM each, the energy use per pump is:

Scenario #1: 340 kwh/month @ 1728 RPM
Scenario #2: 325 kwh/month @ 1690 RPM
Scenario #3: 293 kwh/month @ 1600 RPM

So you are a quite bit better off with quad 2.5" pipes than a single 4" pipe.

Note too that you could almost get away with a single pump in all of the scenarios and still have at least 3 turnovers per day but the energy use would sky rocket. So two pumps definitely saves electricity and probably will pay for itself fairly quickly.

Scott,
I wasn't disagreeing with the Quad filter. It was your arithmetic on the turn. I got the impression your were looking at a single turn daily. I aim for minimum of a turn and a half daily on residential pools and 3 turns daily on my commercial pools.

Backyard pool,

Your design is basically a Jr. Olympic pool. You'd be best served served incorporating the plumbing the way mas985 indicated on two pumps with independent return piping and directing one of those pumps to Olympic infloor returns down the lane divider.

I'm still curious, what part of town are you in, and my offer still stands. Contact me by e-mail prior to entering into any agreement with a gunite applicator or steel reinforcing company and I'll tell you how it stacks up. I got the impression that you were attempting to go it own your own on your previous thread.
Your not going to hurt my feelings if you don't but I'd hate to see you pay more than fair market value for any aspect of a job the size of yours. If I remember correctly you had an applicator that wanted 170 per yard for a service which isn't worth anywhere near that much.

Just my .02

See ya,
Kelly

MAS985 - I like the 2-suction, 2 return idea. To verify, that is (2) 2.5" suction and (2) 2.5" return lines per pump, for a total of (4) 2.5" suctions and (4) 2.5" returns, correct?

Thanks,
John

Yes, that is correct, 2 lines for each pump for both suction and return. But given that you will probably have multiple returns, you can also go with even more lines, at reduced size, if it is more convienent or cost effective. Usually, I recommend a pool to pad return line for each pair of return ports. This is a good balance of control and cost. Here are the options that will provide about the same performance:

4 - 2 1/2" Return lines (2x2)and 8 return ports
8 - 2" Return lines(2x4) and 16 return ports
12 - 1.5" Return lines(2x6) and 24 return ports

The last one is probably too many return ports for your sized pool but I wanted to included it anyway for comparison.

Also on the suction lines, I would go with a suction line for each skimmer and each pair of main drains (they usually are put in as local pairs). This will provide better control of each suction port. The size of line will depend on how many suction lines you will have but it follows the same rules as the return although I usually like to go one size bigger on the suction side since pumps perform better with lower head loss on the suction side.

If you can give me the expected number of ports for return and suction, I can give you an idea of the minimum pipe size needed. Given that you will be operating at lower flow rates most of the time, the larger sized pipes may not buy you that much performance improvement plus pumps get very noisy if they do not have at least a resonable amount of head loss. Also, how far is the pool from the pad location and how often do you really plan to operate the pumps at full speed? As I pointed out in the last point, the most you should ever need is 2x70 GPM which is pretty easy to handle.

To keep waves to a minimum, and since the pool is outdoors, hove you considered using a gutter system or gutters feeding skimmers and reelable lane floats such as those seen on competition pools?

Scott

poolguynj - what is the most cost effective way to do a gutter system? I have seen the Natare stainless gutter systems but it looks quite expensive. Is there a way to shoot a gutter system w/ gunite as part of the bond beam?

quote" have you considered using a gutter system "quote

This is an awesome setup, my competition 50 meter pools always have gutters. However constructing with gutter and grates is very dog-gone pricey stuff.

quote" Yes, that is correct, 2 lines for each pump for both suction and return. "quote

Even more of a reason to place Olympic infloor returns. Place one of the return pipes on one end with the floor returns and the second pipe on the other end with wall returns on one pump, and with the other pump do the opposite side of the floor and walls from the first pump.
This will allow you the luxury of being able to circulate the entire pool with only one pump alone if the need ever arises.

See ya,
Kelly

Kelly - can you point me in the right direction for the infloor returns? I can't seem to find much on a search for Olympic infloor returns.
I have seen some in-floor returns while swimming in the Lifetime Fitness lap pool but don't know if they are the same unit you are referencing. I noticed they have what appears to be either rust or acid burn radiating out from each return. Is this a common problem with infloor returns, or maybe a result of poor chemistry / maintenance?
One other system I am considering is a product from www.thecirculator.com It is basically a geared return head that makes a revolution roughly once a minute. I spoke with a company rep and he said that if I were to place my returns just above the cove and space them every 6 to 8 feet along the wall, they would serve to circulate the water as well as act similair to an in-floor cleaning system by jetting water across the floor and up the wall - helping to prevent any algae build-up. Do you have any thoughts or opinions on this? If I were to plumb every 8 feet, I would be looking at around 22 returns around the pool....

Thanks for all your input!
John

mas985 - I'm going to sketch up a pluming suction and return diagram and post it later to see if I understand your pipe sizing recommendations correctly...

Thanks for your input!
John

back_yard,

Please take Kelly up on the offer. I just fix pools. Kelly builds them. I've seen the results of what happens when its done right, wrong and really wrong. Kelly does it very well, as does mas985, both of whom have forgotten more that I will learn about gunite pool construction.

Scott

Hi Scott - I sent Kelly an e-mail a little earlier.
Kelly - did the e-mail come through?
I'm definitely going to heed the advice of the experts. Right now I'm trying to learn the ins and outs of pool construction and develop a realistic budget in the process. When it comes time to break ground (which will be several months from now) I hope to have as many of the details worked out as possible, as well as bids from recommended contractors in town. Right now, I'm mainly trying to understand the concepts and get opinions on different aspects of the pool.
Thanks for everyone's input!
John

Olympic infloor heads is just a nickname I made for these return style fittings. Here's a link to some of the fittings.

Here is a link that might be useful: Olympic infloor returns

I didn't see an e-mail that I could determine was yours.
Try kelly@atlantispool.com
I've been having some major problems with my internet service provider accessing the web, and my e-mail send/receive functions for the past couple of weeks due to the new Highway construction is what they've told me, LOL!!!

See ya,
Kelly

Hi Kelly / Scott,
A few quick question on sheer descents.
Reading the specifications from Jandy, it basically states that descents require a dedicated line per descent, and a line diameter of 2" for runs over 60'.
It also states that one needs about 10 gallons per minute per linear foot of sheer descent.
Basically we are planning on (6) 24" descents spaced along the back wall of the pool with (1) 36" in the center, overlapping (2) of the 24" descents by 6". At 10 gpm/ft, it will be about 150GPM, or 75GPM per pump.
Questions:
**If I am just adding 24" descents, does it really require a 2" dedicated line for each descent, or will a 1.5" pipe be more than adequate?
**Will it cause any issues to have the descents run off of the standard pool pumps with just an actuated valve to re-route water from the pool returns to the descents... or do I need a dedicated pump just for the descents? (It would ideal to be able to filter the water and power the water features at the same time - knocking out 2 birds with 1 stone...)

I'm still working on sketching up piping lay-outs - will post once I have 1st drafts complete.

Thanks!
John

Kelly - did you get my e-mail sent last night?

How far away will the descents be from the equipment?
I don't think 1-1/2" lines are sufficient to drive a manifolded set. I can run 3 24" descents off a single 2" feed if I have enough space to make a loop that will equalize the pressure. I also like putting 2 way valves just before each sheer to ensure a balanced set.

I would loose the 3 footer. 12 foot of sheers will be LOUD. If you must have the 3 footer, I suggest putting it on it's own 3/4 HP pump and valving it if it's too much.

How often do expect to run the sheers? Frequent and extended periods running them off the pool system will affect the chemistry. For example, free chlorine now has a substantial opportunity to escape before getting in the pool Another is a potential drop in Alk and pH levels.

If you expect frequent usage, putting them all on their own pumps would reduce the lost free chlorine. That will help prevent algae and other biologicals from taking advantage of low chlorine and high sun opportunities.

Scott

Here's my 1st Draft of Skimmers, Main Drains, Overflow Drain, and Backwash plumbing.
(8) 2" Lines for Skimmers (4 for each pump) each on individual line for ability to control each line w/ ball valves
(2) 3" Lines for Main Drains (1 for each pump)
(1) 2.5" Overflow line to street pop-up head for rain storms
(2) 2" lines to sewer clean-out for filter back-washing

Here is a link that might be useful: Drainage Plan

back yard lap pool:

I have a pool roughly 1/2 the size of yours @ 34,000 gallons and thought it might be helpful to share my plumbing specs with you:

- 1 Intelliflo VF pump
- 1 Quad DE-100 filter, using Aqua-perl instead of DE
- 11 returns on a 2" looped pipe, each with a 3/8" orifice
- 2 bermuda skimmers with a 3" pipe on each back to the pad
- quad mdx drains (instead of 2 mdx/sdx pairs) piped through a leaf canister and back to the pad with 3" pipe
- 2 1/2-3" jandy valves
- 2 1/2" plumbing minimum @ the pad
- sweeps, 45s & Wyes instead of Ts almost everywhere

I am running 16 hrs/day @ 35gpm for 2 months now which is about 1 turnover/day. At the moment the system is running @
4 psi, 1625 RPM and using 345 watts, which is less then $0.70/day @ my electric rates.

I have been running it about 2 months without any problems.