Hi Ernie,
I thought about using a pond liner but decided against it. My thought is if I ever decide to expand the system, haveing a little experiance building a tank might help.

Hi Badflash,
I originally intended on using marine plywood however, I read on monster fish keepers it wasn't necessary. Outdoor and marine plywood are designed to withstand rot and delamination from moisture and high humidity. Although you can use a "c" grade exterior plywood, filling all the knots and other discrepancies requires allot of work.

I have never worked with fiberglass but looking at how others are doing it doesn't appear to be difficult. I will be seeing my friend that works with fiberglass this weekend. I am trying to figure out why, once the frame is made and the plywood is cut to fit, they don't fiberglass the plywood first, (on a saw horse) assemble or attach it to the frame, and then fiberglass the corners and over any screws. I would think this would be simpler but there may be a reason it is not done in this manner.

I am still not 100% sure this is the way I want to go. I will more then likely start the build this winter so I have allot more time to do the reasearch and decide.

I am trying to decide if this guy has to much time on his hands. http://www.youtube.com/watch?v=CU9x_W9X ... re=related Regardless, it's a nice system