Return pipe size...

[rob1116]

I'm sure it's been asked several times, but I've been sifting through search pages for hours now I'll make it quick!
Setup will be ~8' of head, one 90° elbow, with a Mag-12. The sump is fed by a 1.5" PVC pipe overflow. I see everyone recommending up-sizing the return pipe (from the pump outlet to the display) from the 3/4" fitting.
My question is, will I see a noticable difference between 1" pipe, and 1.5"? I understand that the oversized pipe reduces losses associated with pipe friction and turns... but isn't 1" enough to limit those losses?
Also, an 8 foot column of water straight up, sitting right on top of the pump outlet... seems like a lot water to push for this little pump no?
Thanks in advance, once again, for your help.

 

[rob1116]

Disregard this post... I got my Mag-12 today and it says right in the owner's manual that 1.5" is required to achieve maximum flow.
So 1.5" it is then. Thanks anyway!

 

[fender]

For future referenc:
PIPE SIZE
MAX. FLOW GPM (Gallons Per Minute)
MAX. FLOW GPH (Gallons Per Hour)
1/2 "
3.5
210
3/4"
6
360
1
10
600
1 ¼"
20
1,200
1 ½"
30
1,800
2"
60
3,600
2 ½"
100
6,000
3"
175
10,500

 

[bigmac]

Rob,
I'm a little confused (nothing new) you have an overflow with a 1.5" bulkhead and your running the 1.5" PVC down to the sump, right?
Its crazy that Danner sets up the Mag 12 with 3/4" fittings and then says to use 1.5" line for max flow.
Mark

 

[rangermonroe]

I'm confused as well. 11/2 PVC is some monster pipe to be using for a return line. The pump w/ 3/4 inch fittings will only pump a volume of water 3/4 inch. Any gain in flow would be due to lowering the "friction loss".
I have my sump fed by 2 one inch overflow boxes and a 3/4 inch return that I have to gate down to keep the pump from sucking the sump dry. I have about 4' of head

 

[rob1116]

Well, I guess the idea is that for applications where no pressure is required, and maximum volume is preferable, you should provide a very large pipe to eliminate restriction. 1.5" does sound like alot, but it's right in the Mag-12 manual!
Just to clarify: The tank, (not mine) will utilize a HOB overflow that I just finished building. (Came out pretty good BTW) The overflow uses a 1" square syphon section that runs the length of the box. (Similar to CPR I guess). There is a 1.5" bulkhead in it, running 1.5" PVC down to a refugium/sump in the basement. The return from the sump will consist of a Mag-12, with a reducer on the 3/4" fitting, bringing it to 1.5". The pipe then travels ~8' back to the display on the main floor, then goes through a 90°, and a 45° into the display. Let's call it about 10' of head. The Mag-12 lists only around 600GPH at this height. I hope I get that much. Of course, a bleeder line returning to the 'fuge is in place aswell, in case I get too much... but I don't think that'll be a problem.
Wish me luck... we, (my friend and I, it's his tank) are installing it tomorrow. I hope the overflow works! If it does, I should start selling them. I can probably build a nice one for $50CND.