Plumbing Pressure -Pipe size

Jake007 · 03/07/2010, 08:36 AM

I am plumbing up my new 120G from an external blue line pump (1200GPM). I have two returns (megaflow unit). I plan to run one line up from the pump then tee off so I have two lines going to the tank. I am not sure how much flow a 3/4" vs 1" line can flow.

Q. Is it best with plumbing to have a wider pipe (1") most of the way (less friction loss) and then neck down to 3/4" close to the tank at the tee off spot? or does that loose pressure just before entering the tank since the 1" gets split into two 3/4" pipes?

Q. Or is it best to just run 3/4" all the way both from the pump and after the tee?

Q. I was planning to use shut off ball valves in each return line. Each line is 3/4", the 3/4" ball valve looks like it necks down a little at the ball. Should I use the 1" ball valve to maintain the full 3/4" straight flow.

Chris27 · 03/07/2010, 08:52 AM

Make a 1" manifold and then T two 3/4" lines off of it - doing it this way you should make the most use of the pump by having very little plumbing restriction.

MayoBoy · 03/07/2010, 10:39 AM

20 gpm in 1" pipe gives you a velocity of 9.4 f.p.s. 10 gpm in 3/4" pipe gives you a velocity of 7.8 f.p.s.

I would go 1" out of the pump for 6" or so and then a 1" manifold as Chris27 says. Valves in 1" and then bush down to 3/4" after the valves.

Jake007 · 03/07/2010, 06:52 PM

Alright so 1" pipe is less loss = good. After it splits, 2- 3/4" pipes = 1.5" pipe which is a larger area so the velocity decreases.

Thanks.....

Fish Ace · 03/08/2010, 06:38 AM

I would run 1" all the way and then tee it to 3/4" under the tank it's self.

RocketEngineer · 03/08/2010, 09:41 AM

Jake007,

Actually two 3/4" pipes about equal one 1" pipe. You have to add the cross-sectional area, not the diameters. If you really want to increase flow, consider using all four bulkheads in the megaflow overflows as drains and do the return lines over the top.

RocketEngineer

Fish Ace · 03/08/2010, 09:56 AM

I'm assuming you are talking about the return line and if you run a manifold run it under the tank. We are really talking cheap money here and who knows what the future brings.

03/07/2010, 08:36 AM	#1
Jake007 Registered Member Join Date: Feb 2008 Location: Orlando, FL Posts: 273	Plumbing Pressure -Pipe size I am plumbing up my new 120G from an external blue line pump (1200GPM). I have two returns (megaflow unit). I plan to run one line up from the pump then tee off so I have two lines going to the tank. I am not sure how much flow a 3/4" vs 1" line can flow. Q. Is it best with plumbing to have a wider pipe (1") most of the way (less friction loss) and then neck down to 3/4" close to the tank at the tee off spot? or does that loose pressure just before entering the tank since the 1" gets split into two 3/4" pipes? Q. Or is it best to just run 3/4" all the way both from the pump and after the tee? Q. I was planning to use shut off ball valves in each return line. Each line is 3/4", the 3/4" ball valve looks like it necks down a little at the ball. Should I use the 1" ball valve to maintain the full 3/4" straight flow.

03/07/2010, 10:39 AM	#3
MayoBoy Movin' on Up Join Date: Feb 2004 Location: Webster Groves, MO Posts: 2,282	20 gpm in 1" pipe gives you a velocity of 9.4 f.p.s. 10 gpm in 3/4" pipe gives you a velocity of 7.8 f.p.s. I would go 1" out of the pump for 6" or so and then a 1" manifold as Chris27 says. Valves in 1" and then bush down to 3/4" after the valves. __________________ Getting sucked back in slowly but surely. Current Tank Info: 27 gallon freshwater planted cube. Amazonian biotope

03/08/2010, 09:41 AM	#6
RocketEngineer Space is big. Join Date: Feb 2007 Location: Maryland Eastern Shore Posts: 3,226	Jake007, Actually two 3/4" pipes about equal one 1" pipe. You have to add the cross-sectional area, not the diameters. If you really want to increase flow, consider using all four bulkheads in the megaflow overflows as drains and do the return lines over the top. RocketEngineer __________________ -RocketEngineer "Knowledge is what you get when you read the directions, experience is what you get when you don't." - Unknown Current Tank Info: None Currently

03/07/2010, 08:52 AM	#2
Chris27 Registered Member Join Date: Sep 2009 Location: Virginia Beach, VA Posts: 4,452	Make a 1" manifold and then T two 3/4" lines off of it - doing it this way you should make the most use of the pump by having very little plumbing restriction.

03/07/2010, 06:52 PM	#4
Jake007 Registered Member Join Date: Feb 2008 Location: Orlando, FL Posts: 273	Alright so 1" pipe is less loss = good. After it splits, 2- 3/4" pipes = 1.5" pipe which is a larger area so the velocity decreases. Thanks.....

03/08/2010, 06:38 AM	#5
Fish Ace Registered Member Join Date: May 2008 Posts: 301	I would run 1" all the way and then tee it to 3/4" under the tank it's self.

03/08/2010, 09:56 AM	#7
Fish Ace Registered Member Join Date: May 2008 Posts: 301	I'm assuming you are talking about the return line and if you run a manifold run it under the tank. We are really talking cheap money here and who knows what the future brings.