im a lil confused as to if we are talking about the same thing, iwas meaning just simply taking a straight clear pvc pipe and having the ends heat bent so that the entire tube would be 1 piece, and you are very correct on the plexiglas vs. clear pvc price. i guess ultimately it comes down to personal preference and budget. i prefer the cylinder look but thats just my opinion. either way you go, its rather basic and pretty easy to accomplish. on that link that i posted, the author stated that the effect of the cylinder pvc actually magnified the fish swimming thru it, i dont believe that the box-style plexiglas will do that. but again, the bigger part is personal preference