Plumbing question
 

Okay so in building my house I was explaining to the plumber how I want piping running from my fish room (in the basement) up through the walls to where the tank will be above for both my return plumbing and my overflow plumbing.

My question is, my Reeflo pump has a 2" outlet...would I be okay if I had the plumber put 1 1/2" piping in the walls? I plan to manifold off some flow from the return before it goes back up to the tank for my equipment in the sump. I figured the 1 1/2" would be all that is needed once I've robbed some flow from the pump through the manifold.

Am I right or should I have 2" still put all the way up. I will be doing two pipes for the return (1 spare for the future if ever the old one got to have issues or got brittle). Once i get to the tank above, the return pipe will be split into a Y of 1" pipe to go as a loop over the eurobrace to the far side of the peninsula. I know that may not make sense by description but if I could draw the picture I would.:redface:

thats how I built mine, no problems on my end.

How long is the line going to be?

About 13' of rise, 2'-3' of horizontal. Max head on the pump is 24'

Mark just remember that you can down grade a pump from the output but its not wise to down grade from the input so if your pump has a 2" going in stick with the 2" but that is my opinion> and that is what i have read too.

I agree, reducing the pipe size on the suction side can and usually does cause cavitation, which will destroy the impellar.

you'll loose some head reducing the outlet from 2" to 1.5", might get some idea of how much from RC's headloss calculator

probably not a whole lot of cost or effort difference though just sticking with 2"

No, probably not a lot of cost...just was trying to save a little space. Plus I didn't figure the pump was actually pushing the entire 2" pipe full of water all the way up the pipe, but maybe it does.

I don't plan on restricting the input. My sump has a 2" bulkhead hole cut to connect to the Reeflo.

keep the elbows to a minimum as well, huge head loss thru 90's

That's why flex PVC is so useful for aquariums.

reducing output
 

Reducing the output from 2" to 1-1/2" will cause the pump to work harder to pump the water up. The further away from the pump the reduction is the better.

Putting a reducer in is equivalent to increasing the head pressure and will greatly reduce the flow rate. From 2| to 1-1/2" pipe you will reduce the max possible flow (at the same pressure) by about 40%. (flow is proportional to pressure x area)

While friction losses are definitely increased with reduction in pipe size the amount is also dependent on flow rate. So to say one will experience a 40% reduction is not correct.

Chances are with you branching off some flow prior to going upstairs you won't even notice a difference between 1.5 & 2". 1.5" sounds like the right size to me.

Guess I should have clarified my response some.

In a hydraulic system if all other values are kept the same, including pressure and friction, the volume of flow will be reduced by the same ratio as the area. There are many other factors that can and will contribute to this, if you are looking to maintain maximum pump life and flow rate, keep the system restrictions to a minimum and as far away from the pump as possible, the longer the pipe is held at 2" the better.

In most pump driven system flow rate is maintained closer than the volume reduction due to increased pressure at the pump. Increasing the pressure increases the work the pump must do to maintain the flow rate and therefore reduces the maximum life expectancy.

If you are going to tee off do so before the reduction to reduce pressure at the pump and maintain pump life.