In article ,
"Charlie Pridham" wrote:
....
John when you come to refill your pond can I suggest you try and pipe the
rain water from your house roof....

Yes, thanks Charlie. Don't worry: I've been an enthusiastic rainwater
collector since the drought of 1976 [when I was a toddler, natch. If
only.] With the aid of my mega-pump http://tinyurl.com/6lm5jq I've
re-filled the pond with the contents of three water butts [1]

I had iris sibirica in there, and also a water lily, both of which have
gone back in. I'll be adding water cress, as advised here.

What is *not* now in the pond, that was before, is half a ton of black
sludge, some of which dates back to previous ponds, and therefore 20-odd
years. Having always known that "sludge is good" (for small creatures,
natural organisms etc), I always encourage it. However I think I went
overboard, so I've cleared it *all* out, and will now allow a natural
build-up, which I'll keep on top of. [on top of which I will keep, to
paraphrase WS Churchill]

Other things which are no longer in there are (1) one ninja fish, which
eluded sight, never mind capture, for two years; the freeze did for it,
along with the fact that I accidentally allowed the whole pond to
freeze over, too thick, for too long: the water turned toxic. (2) 13
frogs, who also fell victim to my carelessness (3) no doubt numerous
smaller creatures such as dragonfly nymphs.

Pond enthusiasts will be glad to note that I carefully sieved the whole
"half-ton" of black sludge, looking for creatures.[2] A smelly business.
I found 6 live frogs, and two dead ones (the other eleven had floated
to the top already). I found NO nymphs, to my surprise. They usually
wriggle furiously and give themselves away in the slime: no wriggling
this time.

Finally: the plan is to let the pond re-start itself naturally (I am
confident of many frogs appearing shortly, and the tadpoles will have a
much better chance this year, without that damned fish around), AND THEN
to keep on top of blanket weed and other pests, with the aid of all the
advice I've received he thanks a lot folks.

John



[1] Hmmmm -- thinks -- that means my pond capacity is about 850 litres
-- never realised that before).

[2] Using a standard mesh garden sieve, into my plasterer's bath, which
has proved *invaluable* from time to time in the 20 years that I've had
it.