Bulkhead

[edc_aquarium]

So I have a 900 gph return pump and I'm trying to figure out what size bulkhead I should have

 

[rayn]

What is the outlet on the pump? 1”? 3/4”? If you stick with the pipe size for the output, you need a bulkhead that will fit that pipe.

 

[edc_aquarium]

What is the outlet on the pump? 1”? 3/4”? If you stick with the pipe size for the output, you need a bulkhead that will fit that pipe.

I was thinking about doing a 1 1/2 in bulkhead and then putting a ball valve on it to adjust the flow

 

[rayn]

Your pump will only push out what the outlet is. Upsizing the pipe after that really doesn’t do much for you.

A ball valve to adjust flow is smart regardless

 

[ca1ore]

Your pump will only push out what the outlet is. Upsizing the pipe after that really doesn’t do much for you.

Depends on the application. Upsizing pipe dramatically reduces friction so flow may be increased dramatically.

 

[BigHildy53]

Depends on the application. Upsizing pipe dramatically reduces friction so flow may be increased dramatically.

Not following the logic here. Up sizing the pipe doesn't change the pump GPH or the amount of head pressure. And the water will expand to fill the pipe as it rises; that's the nature of water. It's not going to shoot up the middle. So there's still friction.

 

[rayn]

Depends on the application. Upsizing pipe dramatically reduces friction so flow may be increased dramatically.

I’m not following either. In my mind the pump has to fill the larger pipe before it ever really pushes water out, or there will be a void in the pipe creating a possible air bubble problem. Ether way I would think pressure is reduced not increased.

 

[ca1ore]

The rating of any pump is based on zero head pressure, in other words the amount that the pump will flow if there is no restriction on the output at all (some pumps state output based on a nominal bit of pipe on the output). Any plumbing that you then put on the output, or any height that you ask the pump to move water against gravity reduces the flow from that theoretical maximum. While it may seem counterintuitive at first, as you upsize the plumbing, regardless of the native size of the pump output, you decrease friction and reduce the head loss. You will see this reflected in all of the head loss calculators. The amount of reduced loss from upsized plumbing will vary based on the pump you use and the height that you are trying to move the water. In my setup, for example, with 12' feet of vertical head pressure, upsizing the pipe from 1" to 1 1/2" got me from about 950 to 1400 gph from my panworld 200 pump (I did also fix some other issues, so not all of the gain was pipe size).