Thanks for all that - really gives me some good insight into what kind
of equipment I can get and what's worth having and what's less good.

In terms of balencing light and CO2 Amano talks about that in his book.
It seems like quite a tricky balencing act which I will probably get
wrong before I get it right. I was going to get a small CO2 biosystem
(yeast and sugar) which comes with a little plastic maze thing which
the bubbles slowly work their way through giving off the gas into the
water. I haven't got room for CO2 cannisters and I would be worried to
leave them alone with my four year old who adores playing with dials
and levers. He would be utterly atracted to the sight of a regulator.
I didn't know that you could get CO2 supplements - are these tablets
which give off CO2? I'm not sure how steady the CO2 would be from a
biosystem so maybe if the rate dropped I could help things along with
supplements.

Thanks again for your advice and help - I really appreciate it.

muddy