I really don't have a great reason for wanting an acrylic back but I have a few reasonably good ones. First, it's way easier to drill into acrylic. If I'm going to build something where water exchange with a back section/ sump/ fuge would be important, I feel that an acrylic back would be more receptive to drilling and modification than a 1/4" piece of glass. Also, acrylic comes in all kinds of colors. If I want a blue or black back to my tank so you can't see into my back section/ sump/ fuge then it is way easier to use colored acrylic than it is to layer glass so I can paint or add in a piece of colored glass which may have lead in it. Then I've got to drill holes in more pieces of glass in order to make the opacity not touch salt water then I've got alignment problems.... Next, it would be a bit lighter and I could build my back section/ sump/ fuge out of acrylic which would diminish the weight even more. I know it could be done in glass, it just seems that if I could get this to work, I would reap the benefits of both, the strength, lightness and versatility of acrylic with the durability of glass.
PRC, I'm trying to build a nano all-in-one tank designed to meet the specific needs of dwarf seahorses. Cool, no?
C