Well what can I say! The ones that look like vacuum-cleaners
are the problem, not the ones with swimming pool pumps, as motors some of those
are passable to keep a clean pond clean.
This is the problem: the
vacuum-cleaner type models are only just capable of doing that mega task. They
are no use for cleaning blanket weed up, despite what the ads say - they are
not capable of sucking up cotton wool with all their extensions attached. In
fact can only suck gravel with one or two extension tubes on and even then you
have to walk the suction pipe back to the cylinder to get gravel out of the
Buy one for its (only) use - keeping a clean pond clean
like dead leaves, fish waste etc.
Don't put all the extension tubes on,
else when cylinder is full and you switch it off, or the machine stops its
self, then what's in the pipe line goes back into the pond.
Most of the
stuff only makes it half way up the extension pipes.
I must add however
that there are some models well above the £200 mark that are not that
bad. But most of the ones you see in garden centers if thay where £50
price would be about right.
If you have a raised pond, and you attach
one end of 1/4" flexi piping to a broom handle and place it on the pond bottom
with the other end several meters up and over pond running away downhill and
you start suction yourself, what you get out of the pond far exceeds any thing
a vacs type hover can do.
But they are good at cleaning water fall
steps - maybe if they where sold as that, with working depths of 12" then
perhaps so many wouldn't be used once then dumped in the shed.