confused with diy sump...help please

[gio28]

for the most part i understand how to build a sump and how it works but i have a few questions.
so there are three ways that water can end up on the floor:
1. causeower goes out and sump fills with water
solution:make sure sump can hold water from tank until water is lower than the overflow
2. cause:reverse siphon by the return pump
solution:drill a few holes in return pump right under the waters surface
3. cause:intake loses siphon so pump pumps sump water into tank and then runs dry + tank overflows. how do you fix this???
the mag drive i plan on getting has a 1/2" or maybe 3/4" outlet...and i want to pvc i use to be 1". how do i do this?
and if i run the pvc from the overflow to the sump...how does it hold in place and not slip off the bulkhead from the overflow? does the pvc need support on the way down? how do i do this?

 

[salt life]

why do you want your return to be 1"? I would run it 3/4 and have your drain 1"
do you have a hang on over flow box or pre drilled tank? if it is the hang on then it should have come with a flex tube to go down to the sump...

 

[i<3reefs]

Well you want to use an overflow box for your intake. They are commonly sold just about everywhere. I suggest getting a U tube style self priming overflow box, instead of the boxes that require aqualifter pumps. The overflow box prevents siphoning unless water is flowing into it. If your sump pump stops working, then the only water that can be displaced into your sump from your DT is water above your overflow box. Your overflow box essentially establishes the water level in your DT tank, they are all adjustable.
The self self priming overflow boxes hold their suction on the water, and when the power comes back on, they continue pulling water into your sump/fuge.
If you are going to plumb from your overflow box to your sump with PVC then you would by the PVC with the internal diameter that fits snugly over your bulkheads PVC external diameter. You would use the cleaner for PVC that is going to be connected together, and then PVC glue.
Some people buy hose from the bulk hose reals at your hardware stores. You can use clamps to clamp the hose to your pvc. Again you would want the hose to be a tight fit on your bulkhead pvc, and whatever you connect it to in your sump.
Hope this makes sense.

 

[gio28]

i got all of that i think thanks. its hard to visualize it but i think i got it.
so im gonna get an overflow box...is an eshopps overflow box good? for a 36 gallon tank and 20 gallon sump is a box rated 600gph sufficient?
im real confused on how to do the plumbing for the sump. could you tell me what to use and how to do it? like what size and type of tubing and how to hook the return to the mag drive pump.
so as long as the intake stays underwater when the pump starts up again the siphon will continue?
thanks for all the help