I made a sump for my 35g out of a 15g tank, 2 tupperware containers and rubber tube to get the flow going where i want. I found containers that rest in the top of the 15g tank which made it a really easy build. I only had to make three holes in the two tupperware containers.
Hole 1 is near the top of the first container.
Hole 2 is slightly lower down in the second container to allow for gravity drainage from hole 1
Hole three is in the bottom of the second container.
I joined the two containers via rubber tube shoved into the drilled holes. Link hole 1 to hole 2 with tube. Then add a separate tube to hole 3. Leave the tube in hole three slightly below the level where hole 2 drains from hole 1.
If you use this method you could use a third container to create the fourth chamber. Its the most simple sump i could think of.
