On Tue, 10 Aug 2010 15:53:08 +0100, Phil L wrote:
Why not just do it like I've drawn in this diagram:
http://tinypic.com/view.php?pic=25ja9gn&s=4

Each butt fills to the top, then overflows into the next, simples.

That means you need a tap on each butt, and you need to keep drawing
water from each butt in turn to avoid water sitting around too long in
any given one, surely? Having them connected at the base would avoid both
those issues (but the OP just needs to have all three butts on the same
level)

cheers

Jules