Anyway, instead of the spider valve, I used my smaller pump (630 GPH - probably still oversized) and connected it straight to the two growbeds. I bought a
Housing for Coralife Luft pump
In full operation, you can see the return line draining in and the bubbles on the bottom of the photo from the air stone.
Both growbeds during a flooding stage. I carved little channels around the outside of the grow beds for the water to move through. Just like at the beach!
The whole system - fish tank on the ground, grow beds up on the deck, with drain pan underneath.
The drain pan is way oversized. I had that 3X3 Botanicare tray, and it seemed a waste just sitting there. It fit nicely width-wise under the 2 grow beds, but it doesn't need to be as large to do the job that it's doing. In fact, it's size means that more water is stored temporarily in the drain pan instead of providing the fish with more gallons to swim in.
All I need to do is to build a box wide enough and deep enough to serve the same function, but I don't want to spend any more money on it right now!
We're supposed to see temps near freezing tonight and early next week. As soon as that passes, I'll start planting.