Thoughts on duck house/duckponics design.

So I recently just acquired the pieces from a solarium for free. Dual pane glazed windows, 3" insulation, sliding door and storm door etc. I'm planning on framing it out to make a 16'x12' greenhouse/duckponics setup.

The pond will be 500 gallons, 16'x4'x12" deep, (elevated about 2' off the ground) made of plywood and lumber frame and lined with liquid rubber or just a pond liner, depending on the budget. I'm hoping it being elevated a ramp covered with astroturf will keep lots of dirt out of the pond and will help prevent a some mud issues on the ground. Also, having the pond and grow table keeps the floor space freed up for the ducks as well. 2" or 3" drain in the bottom with a 1/4" hardware cloth cover to keep some feathers and bigger junk out. That will drain to my first stage filter, (which will be easily accessible for rinsing/cleaning) either skippy, lava rock or coarse sand haven't decided yet, then up to the hydroponic table. I'm thinking now that I should elevate that first stage filter just high enough to put drain valve on it as well for cleaning.

I could add a second stage filter up here before going to the plants but again, undecided as of yet. Planning on using hydroton as my growing medium. I will definitely be adding a fan for summertime and I'm hoping with all the insulation, dual pane windows and it being up against my garage will help the water stay thawed year round with little effort. It will likely connect to the shed that already exists next to where I'm building, just extra nesting space and will stay cooler during summer.

Planning on about 10 ducks in here. Almost 300 sq ft of floor space and 64 sq ft of water. Thoughts? Ideas? Sorry the images aren't any better, that seems to be the highest quality they'd upload.