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scuba1102
06/23/2006, 01:57 PM
I have a return pump with a 1" outlet spliting into 2 3/4" return hoses. What will produce the highest flow / least resistance - Doing the split near the pump or nearer the top of the tank? - or does it even make a difference?

thanks

Mark

clsanchez77
06/23/2006, 02:09 PM
In this case, use the two 3/4" tubes split nearest the pump. The reason being is that the velocity in the two 3/4" tubes is less than the velocity in 1-1" pipe, which translates to less head loss.

In the end, however, it may not make that much difference.

Chris

HippieSmell
06/23/2006, 02:19 PM
The velocity in the 3/4" pipes will be less because of more over all volume, but there is also more over all pipe surface area, so I don't know if there will be less friction. Like Chris said, it probably doesn't matter much, but I always split pipes towards their outlet to reduce the number of pipes in my system. Makes less clutter.

HippieSmell
06/23/2006, 02:22 PM
You know what would be best would be to increase the pipe to 1.5" then split them at the very end into 3/4". That's what I do anyway. Be sure to get all of the 90 degree elbows done in 1.5" pipe, if possible, then have a straight shot for the 3/4".

clsanchez77
06/23/2006, 02:44 PM
Hippiesmell, I did give the fiction loss some thought, but in the end, velocity has a bigger impact than friction coefficients since headloss is based on velocityu squared and friction coefficnetn is linear. But it all theory and the run in pipe is likely short anyway.

I agree with Hippiesmell, I also prefer less clutter and the 1.5" pipe increase is a good idea, especially to accomdate the 'T' fitting that you will need to split into 3/4", those fittings do have significant head loss associated with them.

Chris