1" return pipe or smaller?

[Chris-]

I am having a delima, as usual. I am not sure if this setup is hurting the inefficiency of my pump. Right now, I have a mag-7 pushing into a 1/2 foot long piece of 1.5" pipe. This is then going off to a "Y" where the splits left/right are 1" . The left/right 1" pipes go almost to the edge of the tank where I have 2 45d angles and then goes up 4ft to the top of the tank. It then curves in a U (obviously) and dumps into the tank.

 

My questions is two fold, let me see if I can explain this:

 

1) Is the mag-7 3/4"? out to 1 1/2" pipe slowing my flow, via velocity, when it is traveling down the horizontal 1" pipes as opposed to if I went from 3/4"? to 1" piping?

 

2) Am I losing a lot of flow using a 1" pipe 4' vertical as opposed to maybe 3/4" piping, due to weight of water, or, other factors?

 

I am getting a Ehiem 1262 in the future and I know some are going to say that pump will over come any losses I may be getting from the mag-7, but, I want to get as much water as I can to the top as efficiently as I can. I have other items I will be T'ing off the 1262, so, more water to go around for everything the better.

 

 

I hope I explained it right as I am not a Hydrodynamics major, lol.

Edited April 29, 2010 by Chris-

[sheac12]

I am having a delima, as usual. I am not sure if this setup is hurting the inefficiency of my pump. Right now, I have a mag-7 pushing into a 1/2 foot long piece of 1.5" pipe. This is then going off to a "Y" where the splits left/right are 1" . The left/right 1" pipes go almost to the edge of the tank where I have 2 45d angles and then goes up 4ft to the top of the tank. It then curves in a U (obviously) and dumps into the tank.

 

My questions is two fold, let me see if I can explain this:

 

1) Is the mag-7 3/4"? out to 1 1/2" pipe slowing my flow, via velocity, when it is traveling down the horizontal 1" pipes as opposed to if I went from 3/4"? to 1" piping?

 

2) Am I losing a lot of flow using a 1" pipe 4' vertical as opposed to maybe 3/4" piping, due to weight of water, or, other factors?

 

I am getting a Ehiem 1262 in the future and I know some are going to say that pump will over come any losses I may be getting from the mag-7, but, I want to get as much water as I can to the top as efficiently as I can. I have other items I will be T'ing off the 1262, so, more water to go around for everything the better.

 

 

I hope I explained it right as I am not a Hydrodynamics major, lol.

 

 

For questions like this I always refer to reefcentral's head loss online calculator (http://www.reefcentral.com/index.php/head-loss-calculator). This will give you an idea of what your pump is actually pushing into the tank. The part I really like is you can see how the flow changes depending on the inner diameter of the pipe you use. A draw back of this system is it hasn't been updated with the Ehiem 1262.

 

What size tank do you have? Personally I like to have been 5-8x tank volume turn over per hour on the return pump. So if you had a 90, and went by my guide lines you would need a pump that actually pushed between 450-720 GPH.

 

One thing to add, be careful on how many things to attempt to branch off the Ehiem. There isn't that much more flow on Ehiem then the MAG 7.

[Coral Hind]

The bigger pipe would reduce resistance so I would figure flow would be better with the bigger sized pipe.

[flowerseller]

The bigger pipe would reduce resistance so I would figure flow would be better with the bigger sized pipe.

 

I agree

[FearTheTerps]

You said that after your Y you have both pipes going up 4 ft. Would it make more sense to have 1 pipe rise the 4 foot height then split near the top of the tank??? That would mean roughly 4 ft less pipe you would need, so less friction. It would also help with head pressure too I assume.

[Chris-]

The bigger pipe would reduce resistance so I would figure flow would be better with the bigger sized pipe.

 

I would also on a horizontal plane, but, it was the vertical head that had me curious.

 

 

You said that after your Y you have both pipes going up 4 ft. Would it make more sense to have 1 pipe rise the 4 foot height then split near the top of the tank??? That would mean roughly 4 ft less pipe you would need, so less friction. It would also help with head pressure too I assume.

 

Thats a good call. Though I liked the way I have it "plumbed" now, I may have to rethinks me design.

[Chad]

I am having a delima, as usual. I am not sure if this setup is hurting the inefficiency of my pump. Right now, I have a mag-7 pushing into a 1/2 foot long piece of 1.5" pipe. This is then going off to a "Y" where the splits left/right are 1" . The left/right 1" pipes go almost to the edge of the tank where I have 2 45d angles and then goes up 4ft to the top of the tank. It then curves in a U (obviously) and dumps into the tank.

 

My questions is two fold, let me see if I can explain this:

 

1) Is the mag-7 3/4"? out to 1 1/2" pipe slowing my flow, via velocity, when it is traveling down the horizontal 1" pipes as opposed to if I went from 3/4"? to 1" piping?

 

2) Am I losing a lot of flow using a 1" pipe 4' vertical as opposed to maybe 3/4" piping, due to weight of water, or, other factors?

 

I am getting a Ehiem 1262 in the future and I know some are going to say that pump will over come any losses I may be getting from the mag-7, but, I want to get as much water as I can to the top as efficiently as I can. I have other items I will be T'ing off the 1262, so, more water to go around for everything the better.

 

 

I hope I explained it right as I am not a Hydrodynamics major, lol.

 

First, flow and velocity are not the same thing... Velocity is the speed at which the fluid is moving, flow is the amount of volume that is moving.

 

1) The 3/4 to 1 1/2" at the pump output is a good thing... it minimizes frictional losses which become much more significant the smaller the piping is. If you want more velocity at the tank output, you can put a nozzle that reduces the output area.

 

2) Larger piping is nearly always better... frictional losses of piping rise as the diameter of the piping goes down. I dont remember the factor at the moment (been a while since I needed it), but I think it is something crazy like a power of 4 or something... meaning that the frictional losses in a 1/2 pipe are 4 times higher than a 1 inch pipe.

[flowerseller]

Bear in mind that if you use a pump that is not pressure rated, larger diameter pipe going up and branching will work against you.

The larger the pipe, the more water it holds the more weight it becomes to push the les flow you end up with.

Why all the different size pipes?

[Chris-]

First, flow and velocity are not the same thing... Velocity is the speed at which the fluid is moving, flow is the amount of volume that is moving.

 

1) The 3/4 to 1 1/2" at the pump output is a good thing... it minimizes frictional losses which become much more significant the smaller the piping is. If you want more velocity at the tank output, you can put a nozzle that reduces the output area.

 

2) Larger piping is nearly always better... frictional losses of piping rise as the diameter of the piping goes down. I dont remember the factor at the moment (been a while since I needed it), but I think it is something crazy like a power of 4 or something... meaning that the frictional losses in a 1/2 pipe are 4 times higher than a 1 inch pipe.

 

 

True. I do understand that flow and velocity are two separate entity's, but, I wonder, do they help/compliment each other like torque and horsepower in an engine (which is a whole other scientific conversation altogether).

 

So, power of 4 to a diff of .50" smaller pipe as opposed to a 1.00"? Hmmm, is it linear in that it would be to the power of 2 to a .25" smaller pipe, say a .75" pipe?

 

Which leads to ......... flowerseller

 

Bear in mind that if you use a pump that is not pressure rated, larger diameter pipe going up and branching will work against you.

The larger the pipe, the more water it holds the more weight it becomes to push the les flow you end up with.

Why all the different size pipes?

 

Correct. So, the real question is, is 4' vertical water weight x2 1" pipes the best I am going to get (with less drag) compared to using 1/2" thin wall PVC which could have a 4x higher coeficiant parasitic drag, but, less water weight, using an ehiem 1262........ or...... so insignificant that it really does not even matter, aka splitting hairs?

 

To answer why so many diameters, well, like said above, to help get the water moving as efficiently as possible

 

"The 3/4 to 1 1/2" at the pump output is a good thing... it minimizes frictional losses which become much more significant the smaller the piping is."

 

Now that was all theory. I am not sure what effects going from small to big back to small would be in the real world. I am only using what I know and read.

 

 

 

Also, if I used one return pipe up past the top of the tank about a foot, in the middle of the tank, then T'ed them with a 45d elbow on each side down to the end of the tank, leveled off at/near the rim and edge/side of the tank, would that water coming down help create a pulling effect?

 

I like having water returned on both sides of the tank to try to keep the tank stirred up everywhere along with my PH's.