Ok first off thanks for all the replies second here are pics of the rez and the problem is I think the rez is sitting same level as the buckets. So putting them on 2x4's should raise up the water so its flowing downhill and can feed more buckets
Since the rise is only like 4 inches from the top of the pump that can't be an issue. The main problem with a set up like this is the rez bucket never stays as full as the buckets its always lower water lever than in the regular buckets so I would assume you put a ball value in the rez to slow down the water flow but keep the suction coming in. wondering how the water lever will be raising them on 2x4's. Might want to mention that the all intake and outflow holes are 1/2 inch and it should probably be 3/4 for the recirculation and 1/2 for feeder lines
You could raise the buckets to limit flow from the pump using the head height enough that your drains might be adequate, idk how high that would be though, depends on the pump.
You could add another "y" in the res, or better, build a manifold off the pump with pvc so you have even distribution, with a valve to bleed off some flow from the pump, so it pumps some right back into the res. Probably the easiest way to go. I wouldn't put a valve inline to limit flow, these pumps aren't designed to run with any restrictions, you'll dramatically shorten the life of the pump.
Either raising buckets or valving is going to reduce flow, which is what you need in your situation, but isn't what you really want to do in RDWC.
You really need larger return lines, that'd be the right way to fix it. Your pumping more water in than they can drain. That 1/2" gravity drain line will never flow as much as the pressurized 1/2" feed lines.
Your lucky in your setup with the smaller res, I think it's saved you from catastrophe. I've seen when people do it with 30+ gal res, they pump the water out faster than it returns, end up overflowing the buckets and flooding their area. You didn't have the volume to overflow 12 buckets.
