wrote in message
ups.com...

Is there an off-the-peg device for diverting rainwater from a downpipe
into one of these tanks i.e. so it stops when full etc?

Yes, there is a thing you cut into the down pipe, that will do this,
however, it will also divert any crud into your tanks too!
Second to last item here
http://www.forabeautifulgarden.com/c...s_details.php4

I have mine setup so water goes into a small water butt, via a large pond
plant basket (http://www.arghamvillage.co.uk/produ...tails/502.html) then
through a bucket of gravel.
(The bucket has two large holes in the bottom, with two of the smallest
baskets over them, to stop the gravel escaping!

In this butt, there is a cheap (£20 from Netto) pump with a float switch,
this pumps the clean(er) water into my main storage via some 1" pipe (it's
actually the flexible pipe the cable companies use to run their cable from
the road to your house, because I had some!)

Then on the highest point of my main storage, there is an overflow to the
drain.

I will at some point, put a float switch in the main storage, so when it is
full, the pump in the small water butt does not activate (There is also an
overflow on this smaller butt to the drain)

Sparks...