Would this system work? (help a newbie)

[2trackin]

Sorry for the rough sketch.

I'm wondering if this system would work. I'm extremely new to this and sketched up this idea. I have 2 rubbermaid tanks, one is 50 gallons the other is 150 gallons. I'm thinking the shut-off valve on the bottom of the grow bed would allow me to adjust how quickly the grow bed would drain (if that's even needed). The overflow in the grow bed would be where the water level pumps up too, I would have the media about 1" above that.

1. How big of a pump would I need? Any recommendations on a good model? I'm assuming it needs to handle a little solids.
2. Any recommendations on timers? How often should I run/cycle?
3. Will the fish tank level fluctuate too much? It seems like the media would displace a lot of the 50 gallons.
4. Should the grow bed drain quickly or slowly? I could control it with the shut-off valve.
5. What media would work best with this system?

Any help is much appeciated.

[badflash]

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.