Oxywhat? of Squill wrote:

as a campaigner for old water I'd just like to congratulate you for not
digging a hole, filling with water and shoving in fish all in one
afternoon

I'm not sure all this testing is worth the price of the kits. If the pond
has settled you'll be all right. If not you're going to chuck in chemicals
to raise this and that, and then to lower it again. I think you've left
the pond to settle itself and all will be well

Wow. So far I've just accepted that you're unnecessarily cautious, but I'm
not sure how you managed to get so much wrong in only four lines. Just
because the pond is "settled" doesn't, in any way, mean that it's safe for
fish. Your water may be entirely incompatible with fishy life. There's
only two ways to know - throw in some cheap fish that you won't worry about
if they die, or test.

Just because you _do_ test, doesn't mean that you're going to "chuck in
chemicals". Testing for ammonia or nitrites only every tells you when you
need to do two things - clean the filter and change water - but they're
pretty vital. I wouldn't bother testing for pH, because I think it's a bad
idea to adjust pH if you can help it, and I only test for ammonia if the
fish seem distressed (which, in my ponds has been never), but it's always a
good idea to know what your ammonia is like.
--
derek