Why return pipe is smaller than the drain pipe?

blkdrgn · 04/26/2007, 04:39 PM

I keep on reading that people use smaller sized return pipes than the drain pipes. Why is that? I want to use 1.5" drains. Is 1" returns the recommended size according to the drain size?

sir_dudeguy · 04/26/2007, 04:46 PM

dont know the recommended return sizes, but the smaller return probably has something to do with the fact that gravity can only pull out a certain amount of water from a certain sized hole....where a pump is forcing water through the pipe, so it can be smaller since the water is being forced and not pulled out w/gravity.

danch · 04/26/2007, 04:47 PM

The return is smaller because the pressure can be (will be) higher, since it has a pump pushing it, rather than just gravity.

silverwolf72 · 04/26/2007, 05:16 PM

Any plumbing that will have any large air bubbles in it will have to be larger to move the same amount of water.

szwab · 04/26/2007, 07:09 PM

the drain size is really more reliant on the amount of flow you will have going through the tank. There is a calculator on the home page that will size the drain needed.

http://www.reefcentral.com/calc/drain.php

04/26/2007, 04:39 PM	#1
blkdrgn Premium Member Join Date: Mar 2007 Posts: 250	Why return pipe is smaller than the drain pipe? I keep on reading that people use smaller sized return pipes than the drain pipes. Why is that? I want to use 1.5" drains. Is 1" returns the recommended size according to the drain size?

04/26/2007, 04:46 PM	#2
sir_dudeguy Registered Member Join Date: Mar 2006 Location: Portland, OR Posts: 10,841	dont know the recommended return sizes, but the smaller return probably has something to do with the fact that gravity can only pull out a certain amount of water from a certain sized hole....where a pump is forcing water through the pipe, so it can be smaller since the water is being forced and not pulled out w/gravity. __________________ TAKE...LUCK!!!

04/26/2007, 04:47 PM	#3
danch Registered Member Join Date: Oct 2006 Location: Milwaukee, WI Posts: 614	The return is smaller because the pressure can be (will be) higher, since it has a pump pushing it, rather than just gravity. __________________ Asking dumb questions since '06! Or, a dumby asking questions since '06! Current Tank Info: 29G FW, 75G LPSing

04/26/2007, 07:09 PM	#5
szwab RC Mod Join Date: May 2002 Location: Columbus, Ohio Posts: 15,225	the drain size is really more reliant on the amount of flow you will have going through the tank. There is a calculator on the home page that will size the drain needed. http://www.reefcentral.com/calc/drain.php __________________ Mark "I got a fever, and the only prescription, is more cowbell" ~ Christopher Walken Current Tank Info: AGE 240 Flatback Hex Last edited by szwab; 04/26/2007 at 07:17 PM.

04/26/2007, 05:16 PM	#4
silverwolf72 Registered Member Join Date: Jul 2005 Location: Lake Forrest CA Posts: 1,732	Any plumbing that will have any large air bubbles in it will have to be larger to move the same amount of water.