Haven't heard from Ron K. in a couple years. He must have gotten a real job.
Here is a crude drawing of how I have built them. I will build another with good pictures next week.
Parts List:
2 - Stackable Rubbermaid or equivalent containers ( about 10 inches deep )
Small submersible
pump. ( 50 to 100 GPH )
PVC Parts
2- 3/4" corners
2- 3/4" end caps
1- 3/4" tee with a 1/2" Threaded intake
1- 1/2 connector
4- 3/4" pipe 6" long
1- piece of 1/2" hose
Some grow baskets