Mike wrote:

Hi, new here and new to the world of ponds, don't have weeks to peruse
archives, so please forgive dumb questions?

Really weeks would have been a much better idea...

The new pond is rubber-lined, about 6' deep in the middle, 30' by 40'
oval shaped, guessing about 20K gallons? Fed by spring water, (spring
box makes about 800 gallons a day),

Oh lovely! It simplifies things so much when you get water added
automatically.

Put about 20 feeder goldfish in about a week ago; they were looking
pretty happy, so added 5 (4-6") koi a few days ago.

I really wouldn't have wanted to put koi in there so soon after the
goldfish. You have the advantage that you don't need to wait for a filter
to cycle, but one week seems like way too small a time to wait.

They seem very
happy, but little goldfish are gone, so I figure they became lunch.

In 6' deep by 30 to 40'? There is practically zero chance that you will see
those fish again until they reach 6" or more! They're probably loving it,
but they don't need to come to you for food. The feeders may have become
food for the koi, as there won't be much else there for them to feed on,
yet, but much more likely they're just keeping out of the way of the bigger
fish.

Question is this: Does this set-up sound like it might be OK? I
tested the water and it seems to be within spec, and I have had
aquariums for years, just not a pond. Will this pond undergo the whole
"break-in cycle" since it is constantly changing water?

It sounds like the sort of pond most of us would die for (except that dieing
would probably ruin the enjoyment :-) ). No, it won't ever cycle.
--
derek