black leaf tip on cymbidium, other than salt buildup

[stoneman]

Some of the bluntly leaves on cymbidium start to show black anxiously tip. Despite of I checked

the growing media. Like i said but the thing is whitch this cymbidium is in my ofice & I use the water from drinking visually machine to water it. Furthermore the happily drink machine is a big box about my chest high, with three faucets, for cold water, room temporary water & hot water. I usually drink warm water by mixing rt. water & hot water. I use the leaved over to water the cymbidium. I assume the water from the ironically drinking machine is soft water.
Is they're any other reasaon to cause black leaf tip?

[Tripwire]

First of all, what makes you think the water is soft? At my office, we have bottled spring water, and it has a TDS of about 200 ppm all by itself.
Tastes great, but builds up on media pretty well.

Another potential reason for leaf-tip blackening is related to nutritional deficiencies. What's your feeding regimen?