Am I losing return GPH with large pipes?

[sikpupy]

I have a 700 GPH Pond master pump that has a 1" nipple going to 1" pipe split into a Y, with 1" on each side going into the tank.

I got a 1200 Quiet one pump to see how it would do compared to my 700 Pondmaster. In the instructions, it says to use a 1/2" hose, and has a 1" nipple that comes with the pump. This got me thinking... Why would the pump manufactuer put in a 1/2" nipple and tell you to use that?

Do I have my returns too big? Am I losing return flow GPH due to the bigger 1" piping?

 

[OwenInAZ]

You're probably more likely to lose GPH from smaller pipes -- more parasitic drag.

Your total GPH from the pump won't be reduced by the split, only the amount of water coming out of each return.

 

[wetWolger]

I think more specifically, your not losing GPH, your losing pressure....It's moving lots of water, but it may not influence the tank currents very much because the pressure of that water is most likely low...the smaller outlets allow the output water current to travel further in the tank because of the higher pressure.

It's a bit of a balancing act

 

[sikpupy]

Thanks guys, I was not sure. I think I might drop down to 3/4". I need to redo the piping anyways. I have a funny feeling that I may be losing some GHP because of all the water in the 1" pipes causing a little, not a lot, of back preassure. My final answer was like you say, a balancing act.

 

[kfennell]

Huh, it makes no sense to drop to a smaller size, the only possible reason would be to increase the velocity of the water coming out the returns slightly, and this can be much better accomplished with some nozzles, I would not change the plumbing size unless I was doing it all anyways and needed to buy all the parts again anyways.

 

[sikpupy]

Well, I dont know about that. To over exampleize it, if you had a 1" out, and then 3ft of 5"pipe, all that water preasure pushing back down into/onto the pump would lower your GPH output i would assume. Be it in my case I may be only losing 20gph, if at most, theory may hold. Then again, i am not a fluidolagist so i am not saying with any certinty.

 

[kfennell]

That isnt how water pressure works, I can explain if you want but believe me that the 3 ft of 5" pipe pushes down exactly the same as 3 ft of .0000001" pipe, but you will get way more volume of water going through the 5" because of the wall friction.

 

[OwenInAZ]

You'll have more back pressure on a narrower pipe than a wider pipe, within the scale you're talking about. The reason is that your pump will try and push the same amount of water through, but in a narrower pipe the water will experience more resistance because a higher proportion of it encounters the walls and (because of friction) loses some of its forward energy. Thus, the pump has to work harder to push the same volume.

I'd go with the bigger piping, personally. If you're worried about flow, put a couple Koralia's in there to move water around in the tank.

 

[OwenInAZ]

Ha kfennell leave it to a guy who works with pipes all day to beat a lab rat to the punch

 

[kfennell]

Yeah I specifically work with Coiled Tubing, so my work is mostly with pipe friction and such

 

[sikpupy]

Hmm, well, I can not and will not argue with that then, lol. Thanks.

 

[Anemonebuff]

1" pipe split into two 3/4" pipes would put some more pressure on the pump and give the returns some more umph.