black leaf tip on cymbidium, other than salt buildup
 

Dear All,

Some of the leaves on cymbidium start to show black tip. I checked
this newsgroup and people are saying that it is due to salt buildup in
the growing media. But the thing is that this cymbidium is in my
office and I use the water from drinking machine to water it. The
drink machine is a big box about my chest high, with 3 faucets, for
cold water, room temp water and hot water. I usually drink warm water
by mixing rt. water and hot water. I use the left over to water the
cymbidium. I assume the water from the drinking machine is soft water.
Is there any other reason to cause black leaf tip?

Thanks,
Tiff