At the recent Redlands International Orchid Festival, I challenged
myself by purchasing two Phragmipediums: Phrag. St. Peter and Phrag.
Don Wimber. Now, I've been growing orchids for maybe four years, and
I'm pretty good at keeping Phals, Dens, and Catts alive (and even
getting them to bloom once in a while). Living in Broward County
Florida, this doesn't take too much work. I am lucky
enough to be able to keep my orchids outside in the elements, and most
of my battles involve finding just the right amount of light in my
back patio (or trying to squeeze in one more plant into "just the
right spot").
I've heard that the Phrags, especially, like ultra-pure water. This
is the rainy season, and lately we've been getting almost too much
rain, so clean water is really not a problem at present, but my
question is this: Will supplementing the not-always-so-regular
rainfall with water from the Pembroke Pines public water supply damage
these apparently delicate plants? The water is "moderately hard" at 3
grains/gallon, and the PH is slightly alkaline (8.8 - 9.4). Sodium,
calcium, and traces of magnesium are to be found in the water samples.
And, while I'm thinking of it, what's "just the right spot" for these
plants as far as light goes? Can they tolerate direct sunlight
(filtered through a mosquito screen) for any period of time? Should I
put them with
my Phals (which get only a tiny amount of direct sun), my Paphs (which
get no direct sunlight at all), or my Catts (which get quite a bit of
direct sun)?
Should I be worried about the high summer temperatures? Will the 90's
of South Florida end up killing these plants?

Thanks for any comments!