Multiple Tank Sump

[gregswimm]

I have a 20g acrylic tank that I want to turn into a sump for a 29g and 20gL (maybe even a 10g if i can get it close enough to the other tanks)aquariums. The acrylic tank has dimensions of 24"x13"x16" and has 2 pre-drilled holes at the top. They are freshwater tanks containing fish from lake Tanganyika, but I figure, when it comes to sumps I better go talk to the salt water people . The 29g I can drill an overflow the 20g I cannot. How can I set it up to best accomplish my goals of having Mechanical and bio filtration, possibly even a chamber where I can keep rocks/other water hardening 'things', and a refugeum (for fry or injured fish) if I have extra space.

I have never done a sump before, any and all advice/blueprints would be amazing.
I should also note that I want to do this as cheaply as possible.

Here is the tank in question

 

[gregswimm]

I have decided that ill drill a 1.5" hole in the bottom of the 29 to fit the 3/4" bulkhead for a 3/4" drainpipe. And for the 20gL im still not sure whether to go with a HOB overflow or just drill an overflow(but the tank has fishes).

In the sump I figure they will pour into mechanical filtration, empty under the first chamber and rise through bio filtration; where it will spill over into a refugeum. Then somehow make its way to where the return pumps are located.

Would it be better for the water to enter the sump being piped down to the bottom of the mechanical filtration and spill over into the bio filtration?

Also do I need precisely the same gph pump as im expecting to exit the tank? I found a calculator that says for 300gph ill need a .72" drain pipe. I have been unable to find a 18/25" drill bit or a bulkhead/pvc pipe that will fit that, so i rounded to 0.75 (3/4), this puts me at 330gph drainage.

My head

 

[Lufbramatt]

some good info here:
http/www.fmueller.com/home/aquaristic/240g/technology/filtration/

and here:
http/reefkeeping.com/issues/2003-01/gt/index.php

 

[TropicanaFish]

You can buy a overflow box to set on the back of he tank with osu so that ou nt have to drill anything.

 

[DrRob]

What's the surface area of the tanks you want to sump? You need to remember what happens if the power goes out, which is generally that the return pumps stop and the overflows carry on until the level drops by a small amount.
 
Half an inch of surface from 3 tanks can be a hell of a lot of water space that you'll need to leave in your sump as a just in case.
 
As for overflows, they need to be bigger than the flow of the return pump, otherwise any furring up of the pipes with algae with leave your display tank overflowing. Worth remembering that the pumps will have to work against the head of the pipe height, and any drag from the pipes, so you won't get their full output.

 

[gregswimm]

this topic is so old lol.  I am not planning on doing this anymore.

After sumping my saltwater tank, this totally isn't worth the effort.  I also don't have the room.  If I move however I will be connecting all my systems and incorporating a FW skimmer. 

 

[DrRob]

Not awake, missed the year and read March not May. Was wondering why you were asking. I suspect I need sleep.