"Joan" wrote in message
news
(brevity snips)

Do you really have to do partial water changes in ponds if the water
chemistry is okay?

You'll surely get different opinions on this subject. I believe DS
(dissolved solids) build up in the water that should be removed. Plants and
filters don't necessarily remove them. I do partial water changes on both
my ponds and a yearly or every-other-year cleanout. Mulm builds up on the
bottom that the pump doesn't get, even though the fish may stir it up. I've
never had a fish die with these total cleanouts. In fact the clean fresh
water almost always stimulates them to spawn.

Do I really have to drain the pond every few years for a major
cleaning, or can I just scoop the gunk up off the bottom with a net?

That stirs up foul gasses which are not healthy for your fish and leaves all
the "fines" behind. It also doesn't remove all the dissolved solids in the
water.

It took so long to get the water just right; I hate to rock the boat.

What was it before it was "just right?" My GF and koi have thrived and
spawned in water from a PH of 7.6 to 8.2. Your 8.5 is a little high. Just
curious, why do you keep it so high?
--
RM....
Frugal ponding since 1995.
rec.ponder since late 1996.
Zone 6. Middle TN USA
~~~~ }((((* ~~~ }{{{{(ö