I'm going to try and post some pics. Wee Zard said I may have difficulty since I have less than 50 posts . Stay posted, I'm going to give it a try. Won't be until tomorrow.

In the meantime; Yes it's gravity it just drains back to the res. The pots don't fill up. It's a root spraying system. The sprayers are in the tubes and just spray the root structure. It drains back within 60 secs.

I'll do my best on pics in the morning.