piping size question?

[J-P]

what size pipes would one be using if they were pushing 1200 gph?

I have an old pump that I believe out puts that but wanted to make sure my piping wasn't too narrow.

[thegrun]

Maximum Achievable Flow in GPH
300 GPH 1/2”
720 GPH 3/4”
1,200 GPH 1”
1,,600 GPH 1 -1/4”
2,600 GPH 1 -1/2”

[J-P]

ohhh thank you!!!

that should be a sticky!!!

[CreativeGuy]

@thegrun: may I ask where you found your data please? (not being argumentative, just currious as there are many sources).

Flow through pvc pipe is not always a simple answer; just google pipe flow and you shall get a variety of charts with various ranges. There are several factors which effect flow not only the pipe (rigid vs flex, different manufacturers, friction loss) such as fittings, valves, velocity, inlets, discharges, head, pressure, CV ratings of components, restrictions, etc., all can influence flow. Even whether on the "suction" side or "pressure side" of the pump. There are formulas that take these aspects or factors into account and give a better representation of expected flow.

http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml
Gives a range of flows depending on PSI and/or velocity.
On the suction side of a 1.5" flex pipe which is in the range of 6 ft/s would have a flow of 2,100 pgh; yet on a pressurized pipe pushing 20 psi to 100 psi (flow rate of 12 ft/s) would be approximate 4,800 gph; and an indicated maximum of 18 ft/s would be over 7,500 gph. Pressure greatly affects flow rate. At higher velocities several things occur which may not be well suited to aquarium systems because of noise and/or power requirements of a high pressure pump.


Head differences effect flow as reflected in flow calculators such as Bean's
http://beananimal.com/articles/hydra...-aquarist.aspx
Where at a head of 7" flow is estimated to be about 2000 gph through a 1.5" pipe and at 16" of head the flow can increase to 3,000 gph. Or in the case of a sump in the basement or crawl space below with a head difference of 84" (7') the estimated siphon flow could be as high as 7,000 gph.


Flows can also be affected by in-line components like balancing valves (CV is a rating given to many components) or number of elbows or type of discharge nozzle. Eductors can be situated on the end of the discharge to increase effective flow in the tank by 3X to 5X, but they require a higher pressure (usually 10 psi to 30 psi) to perform properly.

Just saying that the answer may not be as simple as you would like. It would be prudent to take into account all the components and pertinent factors of your specific set up. I have been trying to design a complicated multi-tank system that has sumps and tanks at different elevations (head), closed loops, siphons and drains and it has been one of the greatest challenges to figure out and select appropriate pumps.

Like to see what others have to say. There is always so much more to learn, especially in hydraulic flow in piping systems. I don't have all the answers and keep seeking information and having discussions with many manufacturers of products and components, pumps, controllers and design softwares. Haven't finalized my design yet. Expecting to start playing with a temporary system to try various assemblies and pumps to see how well they work before completing my build in my 600g main display tank. I know it will be a combination of returns, closed loops, seaswirls with eductors, and likely a couple of vortechs.

Wish everyone good success in whatever they choose to do.

[Andrew17030]

The question is a little vague and there are many things that add up to how much water can come through a pipe at a given diameter and at a given speed.

All pumps are not equal, some pumps are built for high pressure applications, and some are built for high flow applications. IMO, most are a compromise some where in the middle. If you tank a pump built for a pressure application and a pump for high flow application rated at 2000 gph and hook them up to a 25' vertical 1" pipe. The flow rated pump many not even have enough power to get the water up 25'. Why would one ever buy anything but a pressure built pump then? Because they use less power, smaller, and are cheaper. These are very broad statements and close to overgeneralizations but the meat is there. What creates pressure in plumbing resistance to flow or head pressure. There is a head pressure calculator on the RC home page. You select the pump and then describe your plumbing. Even if they do not have your pump it will help you understand things that impact your plumbing's flow capacity and your pump's ability to create flow within your plumbing.

[Andrew17030]

The question is a little vague and there are many things that add up to how much water can come through a pipe at a given diameter and at a given speed.

All pumps are not equal, some pumps are built for high pressure applications, and some are built for high flow applications. IMO, most are a compromise some where in the middle. If you tank a pump built for a pressure application and a pump for high flow application rated at 2000 gph and hook them up to a 25' vertical 1" pipe. The flow rated pump many not even have enough power to get the water up 25'. Why would one ever buy anything but a pressure built pump then? Because they use less power, smaller, and are cheaper. These are very broad statements and close to overgeneralizations but the meat is there. What creates pressure in plumbing resistance to flow or head pressure. There is a head pressure calculator on the RC home page. You select the pump and then describe your plumbing. Even if they do not have your pump it will help you understand things that impact your plumbing's flow capacity and your pump's ability to create flow within your plumbing.

[Ron Reefman]

This one is too easy. I know this isn't the perfect answer, but it's the obvious one! What size is the ID of the outlet side of the pump? That's what the manufacturer has suggested, so I'd go with that. If your run is going to have lots of elbows, you might go up one size.

[Chris27]

It's an easy answer......3/4" hose or pipe.....that is after all what a majority of folks use considering locline is only available in 1/2" and 3/4"...

[nmcgrawj]

Originally Posted by Ron Reefman

This one is too easy. I know this isn't the perfect answer, but it's the obvious one! What size is the ID of the outlet side of the pump? That's what the manufacturer has suggested, so I'd go with that. If your run is going to have lots of elbows, you might go up one size.

Mag recommends 1.5" as a minimum to get max flow. 3/4" outlet on a pump is not the same as a long 3/4" pipe.

3/4" vs 1 1/2" is a difference of 100+gph. Use the calculator here...you'll see.





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[nmcgrawj]

Originally Posted by Chris27

It's an easy answer......3/4" hose or pipe.....that is after all what a majority of folks use considering locline is only available in 1/2" and 3/4"...

You're right...and most people leave a lot of flow on the table. Wasting money buying bigger pumps and not getting the flow out of them.


I made this post in another thread...


Mag 9
5ft, 1 90*, 1 45*
no valves

Using the calculator....

.75" diameter: 616gph
1": 705
1.25": 746
1.5": 755
2": 762
2.5": 764
3": 765

I know when I was planning mine a guy said he redid his pipe from 3/4" and increased it....picking up flow. You want to have the least resistance on the pump...as you see u gain flow until a certain point.

Follow what the manufacturer suggests. They don't care what size pipe u buy....




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[vwwanksta69]

Originally Posted by nmcgrawj

Mag recommends 1.5" as a minimum to get max flow. 3/4" outlet on a pump is not the same as a long 3/4" pipe.

3/4" vs 1 1/2" is a difference of 100+gph. Use the calculator here...you'll see.





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My buddy bought the Mag18 and it did say in the instructions to use 1.5" piping. The outlet on the pump is 3/4" as well. We could only get his piping up to 1.25" due to HD not having all the parts we needed.