Do a little more reading here. Lots of designs, but yours has it backwards. You need more grow bed that fish 2:1 or 3:1 are the most used (plants to fish). Gravel beds should be about 12" deep. If you are rafting rather than using flood & drain, you need a filter to remove solids.

Pump sizing should be large enough to ruen over the water in the system a minimum of 2X an hour.