I agree that many tanks seem overbuilt. I understand how the fear of hundreds of gallons of water and your livestock on the floor can motivate some to overbuild. my problem is I don't know how tall 3/4" plywood can support without a supporting frame? I want a 30-32" viewing window on my tank, so the glass will need to be about 36" tall for the overlap. so I'm guessing that my tank will be close to 38" tall.
what pond filter would you use and what media? would you have a pre filter?
I am still in the planning stages..... thanks for the advice
For 38" tall you can build it similar to mine. Just make sure you have the walls tied together at the top to prevent any bows. 3/4" plywood is plenty strong enough as long as you reinforce corners and run a few layers of fiberglass too.
I would use a pool filter with a backflush feature then maybe a sump with a foam prefilter then some scrubbies and pond media. I've read that filter socks are really good prefilters but maybe too good because you'd have to clean them regularly. The foam I use is medium poret so it catches the big stuff and the little stuff gets caught in the scrubbies and breaks down anyway. I only clean my foam 4-5 times a year.
You may want to start another thread of your build so more people can give input. I used google sketch up to draw up my tank before I started building. It's really helpful to see how everything looks before you make one cut.