Pool pump/filter recommend please

[mas985]

If you only have 1 skimmer and 1 return line, your head will be quite high with a full rate 1 HP pump. I estimate over 70 ft of head which is mainly due to the 1.5" 75 ft of suction pipe.

The maximum recommended GPM for 1.5" pipe is about 42 GPM. If you go with a 3/4 HP, the head will drop to 60' @ 57 GPM. At 1/2 HP, the head will drop to 47' @ 50 GPM. These are only approximate since it depends on the pump type.

Here is a web site to help with pump sizing:

http://www.poolplaza.com/pool-pump-sizing-2.shtml

[poolmikecalif]

Basically your telling me that its about impossible to optimize my pool. If I go with a 3/4 hp pump, then I'm slightly overdriving my plumbing. I might be able to live with that, but then, on low speed, I'm basically moving not enough water to turn over my pool. Low speed is 3/32nd hp. Not much flow and thats a lot of water to move. I think I can get maybe 20 GPM or so at low speed, but since TDH goes down with the lower velocity, I have not idea what it is.

To turn over a 25000 gallon pool in 8 hours requires 52 GPM. Since I can only get 44 GPM out of 1 1/2 inch pipe, this is impossible.

Aparrently the 44 GPM comes from the building code requirement to not exceed 8 ft/sec in the pipe. A pipe can technically support the flow, but pipe damage can occur. Thus, I can exceed 44 GPM and the pump shouldn't cavitate or do evil things.

A better match is the 1/2 hp pump, but then I'd get essentially nothing out of low speed, if I can find a two speed pump.

The most correct answer is to add a second suction and return or convert to 2" pipe, both which are essentially impossible on an existing pool. I actually have a second return. That is intended for a pool cleaner with a booster pump. Since the pressure side head isn't a large contributor compared to the suction side, I don't think it would help much.

[duraleigh]

Hi, Mike,

Mas985 has given you some great info but you seemed to shuffle it aside maybe a little too quickly. Two thoughts come to my mind....Could you get your .75 2-speed pump (for the rebate) and run it on high all the time? Seems simple enough.

When you get your new pump and filter, could you replumb your booster pump line to become a suction line...or perhaps perform both functions if you use the booster pump.

I will also promise you can push more than 44gpm thru a 1.5"pipe without harm....been there, done that.

Impossible to optimize your pool? Optomize means doing the best you can....not perfection, but the best you can do with what you've got. I think you can improve your system markedly with a little more planning.

Dave S.

[poolmikecalif]

No, I'm not trying to push his information aside. I very much appreciate it. I agree that getting a downsized pump and running it on high most of the time is a rational plan.

The problem I see is that going too small won't allow me to get a decent turn-over rate.

I've been doing a little more research and it does appear that I can push a bit more flow that 42 GPH even though its not the best idea. Something on the order of 55 GPH or so.

The thought of using the booter line as a second suction line is very intriguing. That would be terrific if I can do it.

The port on the side of the pool is maybe 18 inches below the surface. Would this really work? BTW: The only reason I call this the booster/cleaner line is that what the previous owner called it and there is an unused booster pump in the pool house. He said he threw his cleaner away because it didn't work.

Can I have 2 1.5 inch suction lines and a single 1.5 inch return?

ALso, thanks everyone for helping me through this.

[duraleigh]

Hi, Mike,

I would envision the suction side plumbing something like this...two 1.5 lines, contolled each by a ball valve, coming from the skimmers and the booster line, teeing into a 2"line at least 12" long that goes into your pump. Even if you have to come back down to a 1.5 entrance into your pump, that 2' tee will reduce some turbulence and, therefore, TDH.

The downside is that you would have an open suction line on the side of your pool that could grab somebody and could actually be a little dangerous if, for some reason, you shut off the skimmer suction line. You can buy a little plastic guard to screw into that booster line which will greatly help, but not eliminate, that issue.

If you really wanted to get complex, you could tee off that booster line with some more plumbing so it could be controlled as a suction side or pressure side line. I doubt that's a great idea, but it could be done if you needed to.

Mike, if you can get 50gpm through there, that's 24,000 in a 8 hour period which I think gets you right about where you want to be. Others smarter than me may nix this whole idea but it seems to me it would work nicely.

Dave S.

[poolmikecalif]

I was thinking a standard Jandy 3-way valve that I would just use as a blend valve. Common plastic ball valves don't seem to last too well.

Also, I do plan to use 2" line on the equipment pad between all components. I'll use bushing as the pipes come out of the ground to get to 2". I will have about 2 ft to the pump entrance, so thats not a problem.

The biggest mechanical problem I see with attaching the two lines together is that they are not in nice positions for connecting together. Trying to minimize elbows will be a challenge.

[duraleigh]

Mike, will that valve allow you to have all the ports wide open simultaneously? I don't have any Jandy's..I know they're good quality...but I was thinking a 3-way was an "either-or" valve but not both wide open.

Anyway, I think you're on the right track. An extra 90 turn or so won't add much head and you're really gonna' cut it (head) back if you can get two suction lines going. Let us know how you end up.

Dave S.

[irishkenj]

I'd like some help from the experts too as I'm also looking to go with a two-speed pump.

16x32 foot in-ground w/ vinyl liner. 19,200 gallons before we put steps in the corner last summer.

All 2" pipe.

24" SplashPak Sand filter

2 suctions (only one running at a time) - 1 is 17' (skimmer) run and the other is 27' (vacuum). I believe each has 3 elbows before the 2 near the pump.

1 return is 24' with 4 elbows.

Thanks in advance!! Ken

[duraleigh]

Hi, Ken,

You'll get much more attention if you start a new thread. Much easier for folks to find and subscribe to.

Dave S.

Dave S.