Thanks for you comments. I was starting to get a bit put off by the
amount of nonsense about the trolling issue. Hope it doesnt spoil the
group.

I started with the manual cleaning as I did'nt really know what I was
doing and was'nt about to go out spending lots of time and money on the
pond. Two weeks later I have done both! The temptation know is to
drain and clean just to see whats down there but my gut feel is to just
leave it alone.

There was a huge amount of stuff down there, about a foot deep, mainly
stuff from a large conifor near the pond. However, it did'nt smell and
was easy to scoop out with hands and then net. I thought it would be
too much work to drain but know I've spent nearly a week doing it by
hand I suspect it would have been better to drain etc.

I think at some point I will drain it when I know more about it, I will
start to keep an eye on the water quality and if it get bad then do
something then. It will allow me to secure the hosing for the pump and
the electric cables for the lights and pump too and arrange the
lighting better.

Not sure what a bottom or a verggie filter is, My filter has a biologia
media section in the base - is this the same thing?

I will post some pitures once I get it sorted, it looks a bit dull and
boaring at the moment :-(

Its a small world, although I live in the south of London I actually
work in Cambridge! It's a lovley City but I dont get to see much of it
as I spend my spare time in London - mostly these days on my pond :-)

BTW - your pond looks fantastic. I would love to have something like
that but alas space does not permit - gardens in London are postage
stamp sized compared to what you get in other parts of the world.

Vak