Return Pump Plumbing

[shawnmackey]

Hi, I am in the construction stage for my reef tank, but before I get anything drilled...

I will be using and external return pump to push water from my sump, back to my display. The pump has a 1" inlet and 1" outlet. My question is in regards to the PVC pipe that runs from the sump to the inlet of the pump. Should I oversize this pipe or keep it at the same diameter as the pump's inlet. I've heard you can have problems with cavitation.. although I 've seen plenty of systems online that appear to have the same diameter pipe as the inlet.

[wwest]

IMO, If you are like me you would want to be able to clean the pump. So i would go with 1.5" so you can place a inline ball valve and a union. So in order from sump to pump you would have, 1.5" pipe,1.5" Ball Valve - 1.5" Union Combo, 1.5"pipe, 1.5" to 1" reducer, and then your pump. That way you can shut the ball valve to turn the water off so you can disconnect the pump..

If i could make one recommendation it would be to have a Rubber maid container under the pump so when you disconnect it you wont get water inside of your stand. You can buy a medium sized cake container at Wally-World and cut it down so the pump and the piping can fit comfortably inside of it.

[kyramary10]

With regards to your concern about the the PVC pipe that runs from the sump to the inlet of the pump, I think it is better if you keep it at the same diameter as the pump's inlet.

[saxman]

I'm curious as to why Wes is recommending a larger ID "so a true-union ball valve can be used". I have 1" TUBV's in a few spots on our 100 gal setup. To be honest, I am a HUGE fan of them.

As for plumbing ID, I typically run the same size ID plumbing as the pump inlet and outlet of my return pumps, altho going larger on the inlet won't hurt anything.

JM .02...

[Amphibious]

Here’s why I increase the diameter one pipe size on the suction side of the pump. You are going to want a ball valve and a union on that 1” (in this case) line. A 1” ball valve does not measure 1” through the “ball” thereby reducing the effective size of your inlet to about 3/4”. By going up one size (1 1/4” or even 1 1/2”) you eliminate that restriction. Does it make a big difference? Probably not. But then I was a pipefitter for forty years and tend to be a bit fanatical when it comes to piping. If you read the instructions that comes with your pump, it should tell you “Do not reduce piping size on suction side”.

They make “full flow” ball valves in all sizes, if you can find them. Most “big box” outlets like HD and Lowes don’t stock them. It’s easiest just to go one size larger.

Additionally, on the discharge side, I increase the size of the discharge pipe to accommodate multiple outlets (usually 3/4”). A 1” outlet piped 1” will handle the volume of 2 - 3/4” outlets without significant pressure drop. Adding a 3rd, or more, you will get reduced flow to all.

Dick

[AZDesertRat]

Always increase the size if possible to reduce suction head. Look at any industrial or municipal booster pump and you will always find the suction manifold is much larger than the pumps suction size.
The ball valve for maintenance is a good idea but I would use a true union ball valve to save room and again suction head with fewer fittings. Keep the suction straight if you have room, a direct shot is always better than a angle again to reduce suction loss.