Acyrlic is pretty expensive though so look into the price of that first & determine if your time is worth the money you'll save. I'd be interested in hearing how much you could build one for as I don't really know.
i wouldn't think that it would have to be made of acrylic. it just has to be a box that hangs on the back of the tank with an overflow and a return system, right?
If it helps any. I had a 12 "x4"x9 1/4" (outer dimentions) box made for ~$16 out of 1/4" plexi from the glass shop. AND they glued ot for free (glues spendy and comes in pint sized containers typically) Though they did not garentee watertight seams. It only seeped in one seam. Was planning on making it a HOB box to keep my (modified) Fussion power skimmer in with a powerhead feeding the box and putting some bioballs or crushed LR in the rest of it. Orrigonally i was thinking a side placed mini sump, thus the hight. I probably would have made it 14" high isntead of 9 to make it overflow back into the tank. As well as for more volume for filtration. Though this project is for a 20L. Hope my idea helps spur yours along.
thanks alot, bojik. i was thinking of something similar for my 90. i'm starting to lean towards just doing a fuge out of an old 10gal. tank. seems like less work.
how were you planning on doing the overflow and return to this hob model?
Just taking a 20/201 hagen PH and piping it to the thing via a bit of funny pipe (like whats used for irrigation its bassically flexible black pipe) with a couple elbows. Then putting the end to another into the top of the box. Then a bulkhead connector drilled into the side with a screw in elbow in that. Bassically what i was thinking of doing.