are u going to make it out of glass?
u should make it out of acrylic w/ weld-on IMO
i had only good experience with that except that i used #16 and it looked very messy. so next time i'll go with #3 or #4...
acrylic is also easier to shape like if u want teeth.
TRe...this is the thread I started on my 55gal project... down towards the bottom of the first page is some pics of the sump I built, its built out of a 30 gal long tank (36" long) its laid out skimmer section on the left return in the middle, fuge on the right, HTH
Here's mine.... works great and I am very pleased with it. 30G long.. same as a 55G but shorter...
For the Partitions I used acrylic and cut the notches along the top, then siliconed them in.
Heater is on the left and skimmer and return pump on the right.