I started with a black plastic container and two empty water bottles. The container was from Costco, it had stew (in a bag) in it. I drilled several holes in the bottom to let the water in. The water bottles, I removed the labels, but kept the lids on. I used hemp rope to tie the water bottles to the shorter sides of the container, and then connected those ropes in the other direction, in hopes of making it harder for the ropes and water bottles to slip off. I added a layer of lava rocks and set it afloat in the turtle tank. I added more rocks gradually as they were under water, until most of the rocks are sticking above the water surface. Because they are porous, the more surface area they are in contact with other rocks, the better the water can be transferred up to the top to give the new seeds a good start until they grow roots down into the water.
I'm not sure if it will work or not. I planted the left side with Flame lettuce, and the right side with Green Star lettuce. I planted more seeds than I actually want to have plants growing, but that's largely because I've had issues with germination in my aquaponic experiments before. Besides, these plants will have to grow fast, or have the benefit of numbers to keep up with Minnow's voracious appetite. Does this count as a diet for her? She also has feeder goldfish that she can eat if she can catch (and yes, she can catch them when she's hungry enough), as well as getting ReptoMin turtle pellets. She's actually overweight right now, so I'm cutting back on her pellets.
Amanda's blog about everything, important and trivial.