[prototypep2p]

can anybody give me specs on running the return plumming back to my tank?

[chip]

two things I was told buy an expert were that there shouldnt be any elbows for about 2ft after the pump do to back pressure and that every elbow takes away one foot of head from the pump.other than that there are to many variables with each tank for specs

[prototypep2p]

what size of tubing for the return should I use?

[Jeremy0322]

the drain is more important than the return i think. Check your pump and it will have the size right on the return though i think.

[prototypep2p]

O k so I am using mag drive 950 water pump it has a 3/4" spout should I keep the same size tubing or go bigger?

[Jeremy0322]

no matter what size the return pipe is i dont think it makes much of a difference. That would just make the pressure coming out larger. The pump is controlling the return, but the drain has to be the right size because then your pump wont keep up with your overflow. You could have a 10 foot pipe on the return in theory, all that would really happen is water would fill the pipe and then enter the tank very slowly. I am going to have a 1 inch drain and a 1 inch return, but i will have valves on all of them and be teeing off the return line for the fuge, so i should have pretty good control over the flow.

[Racing1]

It makes a big difference with the mag drive pumps... On or in the box is a paper stating what size to use. I believe it is 1.5 or 2" inner diameter. I originally used 3/4 and then switched to 1.5 in inner diameter and it made a huge difference in flow and also in electricity used....

[prototypep2p]

its only got about 4 ft. of tubing to the tank.

[pogodzib]

For any Mag 9.5 and above pump, you want to upsize the tubing. I'd read several places that Mag 9.5 are actually made for 1" pipe, so I'd recommend at least 1" pipe, if not a touch larger. I've also read on the Danner website that a 1.5" pipe will give the max flow rate for a Mag 9.5 pump. The larger the pipe, the less friction loss there is, but once you get too large, you can run into other problems at well. It doesn't matter where the elbows are in the return line - an elbow is an elbow is an elbow. They all have the same friction (hence flow) loss no matter where they are located. The friction loss is dependent on water flow rate, pipe size, and fitting type. A 90 degree bend has much more friction loss than 2-45 degree bends, so whenever possible, use 45 degree bends. Or even better yet, you can use flexible tubing which doesn't have any sharp bends in it.

[prototypep2p]

thanks pogodzib. I only need to use one elbow and the start of the pump. Leading into a valve then just flexibale tubing all the way up.

[prototypep2p]

Is it ok to put a elbow so close to the water pump? Or does that even matter?

[pogodzib]

The only way that I could see the bend location being too close to the pump mattering is if the flow was so high through the bend that it created a turbulent flow, thus rapidly increasing/decreasing the pressure at the pump. Having a little space in between the pump and bend gives the water some room to stay in its normal flow pattern as it leaves the pump. Upsizing the pipe as soon as it leaves the pump, prior to the bend and valve, should prevent this from happening since it cuts the flow velocity down so then I don't think having a bend directly after the reducer will cause any problems.

[Jer77]

I believe there may be some confusion between the return pipe diameter and the spout diameter. The diameter of the return piping factors in to other decisions when plumbing your system. The return plumbing diameter is a variable which is used along with vertical and horizontal length, number and sometimes placement of restrictive joints like elbows, tee's, etc., and number of outlets to determine the overall restrictive head pressure that Racing1's Mag 9.5 has to overcome while pumping the water back into the tank.

(There are other variables which enter into the equation, but are generally a given for what we're dealing with, i.e. specific gravity and atmospheric pressure.)

There are many online calculators which help bypass the tedious math involved and help you find the actual velocity of the return water. So just some things to consider when you plumb your return:

1. you don't have to use the same diameter pipe that the pump outlet uses.
2. A larger return pipe = lower the head pressure and increase the overall gph. This is the most effective.
3. More joints = higher head pressure and a decrease in the overall gph.
4. Try to use smooth bends instead of elbows to increase gph.
5. More outlets = higher head pressure = less gph.
6. The size of the outlet spout only changes the speed of the water not the velocity, i.e. gph. Yes speed and velocity ARE different.
7. A ball or gate value is an option on the return, not on the drain.

Racing1:

I calculated your head pressure with guesstimated variables, cause I don't know your exact spec's, so I used 4ft. height, 3 elbows and one outlet. The velocity of the outlet water should be close to but probably a little less than 650 gph. Once you know this then you figure out how big the drain needs to be. A 1'' diameter drain pipe will handle up to 600gph so I'd say 1.5'' is the right choice. If you decide to use a 1'' return pipe diameter then the gph will be greater- somewhere around 750gph. A 1.5'' drain will be fine for this too.

(By the way what your expert told you about elbow's relation to head pressure is a rather unrealistic approximation. Each situation is different, and in your case each elbow costs you about 0.26 ft. of pressure, which ain't much.)

[prototypep2p]

wish me luck! lol Thanks alot guys for helping me out with this.

[pogodzib]

Very good answer Jer. I have a couple minor details about your post that I'll be sending a PM to you about.

Your welcome Damon. Good luck and enjoy your tank.



EDIT: I was going to PM you Jer, but you don't allow PM's or e-mails to be sent to you so I'll post it here instead. I've looks at some of your other posts and it looks like we have a lot of the same thought and opinions on things and it appears that you have a bunch of knowledge related to reef keeping. It would be a benefit for all of us here as RB to have you around and posting your thoughts more often.

Now, for the things I was going to put into a PM to you for discussion.

Just out of curiosity, what do you do for a living? Here's the things that I wanted to point out to you - First off, the tedious math is the fun part.

3. Yes, more joints technically adds to the head pressure, but it is very minimal comparatively to the friction loss due to pipe size & length, and fittings (bends, tees, reducers) so it is usually ignored or built into the pipe friction loss coefficient.

5. More outlets can actually increase the gph. Yes, adding additional tees and pipe length after splitting the lines will increase the friction losses, but once the lines are split, there is only 1/2 the water flow rate in each pipe so their is less friction losses in those segments. Plus, if the person is has a pipe size reduction at the outlet spout to increase the water velocity in the tank, having multiple outlets reduces the friction losses at those outlet points as well.

6. The outlet spout diameter changes both the speed and velocity of the water. By definition, speed is the rate of change of distance with respect to time. Velocity is the rate of change in displacement over time. In lehman's terms, for a straight direction such as the water as it is exiting the pipe, velocity is speed with a direction. GPH is a flow rate, or volume per time.

[doctor T]

Jer 77 Dude Speed and Velocity are the same thing. Maybe you mean speed and flow rate?

[boba40]

hey guys,i have got a question.i too am setting up a sump this weekend along with a mag drive 9.5 pump.my overflo set up has a 1 1/2 inch ID pipe which is reduced to 1 inch at the bulkhead and my spray head came with a 1 inch ID pipe.i want to use the 1 inch flex hose on the drain side but i do not like the idea of "slip fit".that sounds like 90 gallons of water on the floor.does anyone use the flex hose?and shouldn't there be shut off valve on the drain side?i think i will use 1 inch pvc.on the return if i am correct there needs to be first a union second a check valve third a ball cock valve.if i use anything bigger than one inch as far as piping what good would that do when the spray head piping is only 1 inch from the bulkhead up

[boba40]

pogodzib,if i am understanding you right,if i were to use an adapter to take my pump from 3/4 in. to 1 1/4 in., use 1 1/4 in return line to my bulk head fitting that drops back down to 1inch my gph would drop but the velocity of water would increase.if that would be the case i need to stick with 1 in. id pipe.

[NATIVEVAMAN]

Just a side note on this thread.There are two kinds of elbows one is a standard elbow that actually makes a hard 90 degree turn.Then there is a street elbow where the turn is rounded and far less dramatic.I recomend the use of street elbows in all aquarium builds.

[Cern]

Originally Posted by NATIVEVAMAN

Just a side note on this thread.There are two kinds of elbows one is a standard elbow that actually makes a hard 90 degree turn.Then there is a street elbow where the turn is rounded and far less dramatic.I recomend the use of street elbows in all aquarium builds.

Also there are 45deg ones if you use 2 of them they make a smoother turn but it takes more fiddling to get your plumbing setup the way you want it. Definitely seconding the 90deg street elbows over standard ones regardless of how you do your return. You could just bend the pipe itself which is what I plan on doing when i stop being lazy and redo my plumbing. :P

PVC pipe bending If you don't have a heat blanket you can use a heat gun. I guess it's a bit more dangerous but you would have to be an idiot to get the pipe to ignite. I've made wide mouth diffusers for my return and split the line to add a top/mid water sprayer (imagine an upside down F). Works great and it's free since you can use any scrap pipe you have laying around. If you try this do not use a torch it will catch on fire and more importantly pvc releases chlorine gas while it's burning.

[Arnold40]

If you are going to bend pipe a heat gun works well. The pipe will become very elastic and can stretch and pinch. 2 things you definitely do not want to happen. You can rent a heat gun from any tool rental place for about $10. If you can fit it, a sweep is a much better option then an elbow.

[NATIVEVAMAN]

I agree with using sweeps,if they fit you cant use better.There is a formula for how close a fitting should be to a pump.It primarily would effect those who have there return pumps outside of the sump.To avoid a problem with cavitation in this circumstance just make sure the pipe goes straight from the sump to the pump.If your pump is in the sump it needs no intake fitting as the intake should be under water.