Without further delay, I present to you our (roughly) 200 gallon aquaponics system, built from re-purposed wood, a cheap pond kit, some PVC, and lava rocks.
Step 1: Tearing down the old raised beds and getting the base built
Thanks to the help of my son, all of the 6" screws were taken out of these timbers, we cut them to size and ultimately built a smaller version for the tank and used some of the pieces for legs and supports on the grow bed. It is worth noting that we were able to reuse most of the screws that came out of the timbers as well so I did not have to buy any.
The size of my grow bed and the size of my tank were based on mathematical calculations made by me based on the amount of pond liner I had available to me. I bought the kit (see picture) on Craigslist for $25 - it was still brand new in the box. The liner was 8x10 so I had to figure on how much I could use of this. I elected to build a tank that was 2x7 x18" deep and row bed was 1x7 x1' deep for optimal root space. Of course, if you are using a different size liner, just keep in mind that your depth will take off length and width from ALL sides (if you go 1' deep, you need to take off 2' from length and width, which works out to 1' all the way around)