My plan has changed a few times, but this is my current plan for building my backyard aquaponics system. My drawing is pretty crude and not to scale, I know, but it's the best software I have available to make the drawing. The grow beds will be two 100 gallon Rubbermaid stock tanks and the fish tank is a 30 inch tall x 4 feet wide 200 gallon HDPE fish tank. I've searched for a 200 gallon HDPE stock tank, but can't find one in between a 169 gallon Behlen and a 300 gallon Rubbermaid. Living in Florida I kind of like the extra height in the fish tank to help protect the fish from hot afternoon sun, but I'll definitely provide shade also.
Some will suggest using a sump to completely drain the grow beds, but due to the extra foot print a sump would require I'm sticking to a gravity drain design. I didn't draw the stand pipe in the grow bed correctly. I've not really determined how that will work best at this point. I'm open to suggestions.
Some will also suggest burying the fish tank deeper in the ground, but since this is an urban subdivision and I have neighbors on both sides I don't want to go any deeper than 10 inches below ground level.
The grow bed will be setting on concrete blocks. The blocks are 7 1/2 inches tall, so three of them will raise the bottom of the grow bed up to 22 1/2 inches.