Pipe Size?

[estcstpool]

As long as you keep the water velocity below 6 ft/sec on the suction and below 8 ft/sec on the pressure side of the pump, you should be fine.

• Size.......6 ft/sec......8 ft/sec.
• 1.5"...........38...............51 gpm
• 2"..............63...............84 gpm
• 2.5............90.............119 gpm
• 3.0".........138.............184 gpm

If you don't need the flow, just keep the flow below 38 gpm.

You should switch to a variable speed pump and run as slowly as possible.

@JamesW How do you test this? I have all my 1.5in piping exposed on an older pool do to a leak and want to upgrade to 2in while im at it. I thought larger is better but could the 2in actually cause me issues?

Moved from here.

 

[1poolman1]

@JamesW How do you test this? I have all my 1.5in piping exposed on an older pool do to a leak and want to upgrade to 2in while im at it. I thought larger is better but could the 2in actually cause me issues?

Moved from here.

A good flow meter can tell you your GPM. With a single-speed pump, you don't have any real options. The actual flow will be determined by all the components in your system (filter, heater, plumbing fittings, etc.) and can't be adjusted. Trying to use valves, either in front or behind your pump will cause more problems than you would like, especially with a 1.5hp pump.
You don't say which pump you have, but it may be possible to downsize by changing the impeller to a smaller one. Best option is a VSP. Two-inch plumbing won't cause you any issues, but really isn't needed if you have no problems now.

 

[estcstpool]

Thanks too late went with all 2 inch.... im sure ill have to replace the pump at some point so i guess im future proofed now.