Stormcooker,
I'd love to help, but I still haven't done my first grow yet, so I don't have any experience with Ebb&Flow.

I will communicate that I think that you're doing the right thing by having your flow for 15 minutes every 3 hours... even during the dark periods. I mean, it rains during the night, doesn't it?

Keep it up! Pretty intereseing thread...