have your in line and the return at the top of the buckets just like the bio buckets
water pressure is a fucking bitch no matter what glues or connections u use
Had this same problem not that long ago. After taking the loaded gun out of my mouth, I broke down and bought Ebb and Flow fittings. That coupled with that marine epoxy (marine/plumbers goop I believe its called), I was finally leak free at the buckets.
Then the lines started leaking, which i combated with doubling up on the clamps( the cheap pinch type), and eventually they stopped leaking. To this day, one of the most frustrating things I have encountered as a farmer.
I still dont trust it, even though its been about 6 months leak free.
Good luck, just keep chugging away and it will all come together.