No body is questioning that water varies and some LFS
have supplements that aren't always needed. I owned several LFS
and did the buying, I know how it works. Nobody here is dense or having a problem with understanding your point. Your argument makes our point, some water is good and some isn't. Here where i live, i don't even choose to drink it. The question was is RO
water recommended in making artificial saltwater for a reef? Answer is almost always yes. Fish only is another story.
I have helped with too many reefs that were messed up from using tap water. A RO
unit is a basic part of a reef setup that is of any size IMO
. Carrying water from the LFS
gets old. If you know your tap water has no dissolved materials you don't want in your tank, sure, use it.
Now back to regular programming.
Acrylic or glass, both work great. I would watch Craigslist and snag the one that suits you for 1/3 of what it cost new.
If you are handy with tools, there is practically nothing, except pumps maybe, that you can't build yourself pretty cheap.
If you build your own tank, I think glass is as easy as acrylic for medium and small tanks if you have a professional shop make the panels for you and grind the edges. Lots of designs on the web.