I dont know much about Banna Chips, but I keep Marine Fish tanks, so I do
know a bit about water, esp Copper.
 
Copper from Copper pipes is effectivly nil.  I have a test kit (availible
from any fish store, for about $20 US) and have never had problems with
water from any sort of pipes, in any of the places I have lived (ranging
from old farm houses with lead and copper pipes to the place I am now, with
a lead/copper feed line from the street and plastic inside).
 
Copper in a Marine Invert tanks (read, corals, crabs, snails and the like)
is a BIG no no, as it will kill them dead, fast.  So Copper is something I
do moniter for on a regular basis.
 
Bottom Line, dont sweat the copper in copper pipes, be more worried about
the lead that leeches out from the solder used to hold the pipes together,
experts have determined that lead solder is unsafe.  AFAIK, even those
amounts of lead (by themselves) are not going to hurt anyone or anything.
When you add lead from another source is when you start getting into
trouble, like peeling paint.
 
Distilled water does not supply the needed minerals or anything, your
correct in this.  Try RO water, its 99.9% pure of unwanted without taking
all the minerals out (just some of them).
 
Just  my 2 cents worth...
 
Dwayne Miller
[Posted in FML issue 3162]