Help plumbing 125G dual drilled overflow box

[rsteckly]

I am in the middle of setting up a new 125G 6ft long tank. It has two overflow boxes with two holes drilled in each box. I am having some issues figuring out if I need to go get pvc piping for it all, or just rubber tubing. I think I have figured out the drain part, but not sure on getting the water back up the holes. Any help would be great. Thanks

 

[ultimate125]

check out my build thread here to see my setup...