quick plumbing question

[Mscott203]

I have a 125g main tank
2 3/4 inch drains to the sump
2 3/4 inch returns from the sump

I have 2 external pumps one is pan world NH-PX-X - 1270g/h
other Little Giant pump 4-MDQ-SC is 880g/h

sump is not drilled at this point for these pumps.

1) I havnt seen it set up this way but can the pumps sit above the sump with a pipe leading from the intake and a 90degree elbow down down into the sump - SCENERIO C - benefit would be no need to drill the sump
2) If I drill holes in the sump so the pumps can intake from the ground level - do I need to drill 2 holes or would 1 larger hole and a pipe with a "T" then a pipe to each pump be sufficient?
SCENERIO A OR B

3) wavemaker - is it ok to put these two pumps on a wavemaker
of some sort so they alternate off and on. or should I consider putting one of the pumps on an ocean motions device or scwd

each pump runs to seperate lengths of pvc in the tank as shown here. (almost all that pvc should be covered up by live rock once up and running)

what do you think?

 

[AZDesertRat]

Centrifugal pumps will not lift water at all, not even an inch. The pumps must be below the water level to work. Drilling is the best method as the up and over plumbing configuration has lots of problems. You are better off with each pump having its own suction so it does not starve the other. Make sure to oversize the bulkheads and holes, again so you don't starve the pumps.

 

[jtarmitage]

I 2nd AZDesertRat, the pumps are not self priming and will need to sit below the water line, and drilling is the only real option. Each really needs it's own bulkhead.
I have no idea about putting these pumps on a wavemaker, but the idea seems wrong to me. I would use an Oceans Motions 4 way or Squirt if you want alternating current. I wouldn't use a SCWD as I have read posts of many SCWD owners wishing they had bought the OM unit.
Also, why not just get 1 new larger pump and not have to deal with the headache of running, and planning for, 2 pumps? You can always just T the line after the pump.

 

[Mscott203]

2 pumps is what I happened to have. I was trying to find the easiest way to use them both and drill minimum holes in the sump, purchase minimum bulkheads, spend the least money, etc.
but I guess its 2 holes, 2 lines pumping water from ground level
thanks for the advice

 

[Beach Native]

What's the thought on having them both pull from the sump?!
I'd recommend using one as a return and one as a closed loop....

 

[Mscott203]

a closed loop would be great, as thats really what im trying to acheive with the pvc in tank, but the thought of drilling the back of the 125g tank is a little intimidating. Its a little easier to bring the sump to a guy I know with the right tool.
I think it would be tough to set it up behind the tank too as there's really very little space to work with.

thanks for the thought though