On Fri, 26 Jul 2013 17:38:25 +0100, Bob Hobden wrote:

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.

And so that a leak doesn't drain them all...

Siphons failing if the water level gets to low can be mostly solved
by having the bottom ends of the inverted U just a couple of inches
above the bottom of each tank.

MBC's are good, large and relatively cheap but are translucent. Algae
will grow in them unless you cover 'em with something opaque.

I'm about to press a similar sized old galvanised water tank into
water butt service. Something that has been waiting for a tuit for
12 years... need to inspect it first to see what it's like inside the
outside is very good.

--
Cheers
Dave.