pipe change

[psuedo]

I am thinking about adding a closed loop to my tank, and I was wondering if there would be any downside to me running from 1 inch pipe down to 1/2 inch to increase water flow when injected back into my tank. I know that the quiet one pumps with the HH on the label have 1 inch outlet which has been compressed into 3/4 inch in order to increase flow at higher levels.

My question is, other than the obvious pressure at the change points ( which would be sealed anyways ) would it cause any other forseeable problems?

[JimE]

If you reduce the 1" line to 1/2" at the tank (effectively a nozzle), you will decrease flow and increase velocity. If you reduce to 1/2" pipe right at the pump you will probably have large friction losses which will significantly decrease flow and of course have less velocity than above example.

Any restrictions put back pressure on the pump, which reduces flow, which will lower the power draw by the pump (its not working as hard). It is not harmful as long as there is a reasonable amount of water passing thru the pumphead.

[Skimmerking]

When I had my FOWLR going in the basement I had a Barracuda Pump going as a closed loop. 4500 GPH in the tank. It was running with 1.5 " IN and Out then as I ran the piping I used a reducer to 1" and teed it off every 1ft. which aloud the pump not to have to much back pressure.
but you are looking at a high flow pump here too.

Pressure pumps can take alot of reducing in pipe after the out let when you have a pump you must deduce right after the pump.

in MAG pump it not good to reduce it causes the pump to shorten life span.

Iwaki pumps are good with reducing the out put .

You dont need alot of flow in a tank to make a difference in a tank. if you arrange the flow you can get pretty much what you want. other then having a 120 X the flow in the sps tank..

[kwirky]

I would try putting an eductor on the return outlet instead.

here's a link that gives you the gist of how one works.
http://www.kthsales.com/website/vendors/Eductors/mixing_eductors.htm