cshenk wrote:
....

I'm thinking vacumn pulling via vent sounds most likely just now but
I'll have her give it another good go with a plunger and change out the
flapper since those are simple cheap fixes.
....

I'd also suggest a good dose of vinegar in the tank and a squirt of CLR
or similar in the ring area of the feeds--I'd still suspect liming there
as a culprit in low flow during flushing, particularly if water supply
is a little or a lot hard...

I suppose the changes enumerated _could_ have changed the venting and
caused a problem but I'd think it fairly unlikely--I don't think I've
ever known of a case that caused measurable/noticeable volume to go down
the drain on a consistent basis. That would imply somehow having a
persistent vacuum problem which doesn't seem too likely to be caused by
wind or other changes of the type you've noted as that would be variable.

Easy enough to test (altho probably not for Mom) by adding a baffle at
the vent exit. Sister good at climbing too???? vbg

--