Want to make a cheap refugium

[Samw]

Man, I've been wanting a refugium for over 8 months now but haven't gotten around to getting it done. The last quote I got for the sheets to build a 7 or 8 gallon acrylic tank was $170. Is that a bit high for an unassembled 8 gallon tank?

What alternatives do I have? I only need 1 of the 4 sides to be viewable. The other 3 sides of the tank can be opague. Is there cheaper acrylic for making a tank and where can I get it?