On 26/07/13 17:38, Bob Hobden wrote:

Too late for you now but I just let the water overflow from one to the
other, each tank is set slightly lower than the first to allow for this
and the only "connections" that are below water level are the taps which
they all need. The first one collects most of the muck off the roof too
leaving the other quite clean. You need taps on all of them so you drain
one first (the dirty one so you can clean it out) and then go to the next.

That's how some of mine are connected. The downpipes are well below the
surface and one leg of a pair of tights is clamped round each. This
collects all the detritus, but requires servicing from time to time.

Don't ask where I get the tights...

--
Rusty Hinge