switching fertilizers!!

[Ray]

If you look at a recent water quality report for San Francisco, you'll note that the alkalinity and TDS is relatively low, suggesting no real need for an RO system (says someone who sells them...).

It does, however, have a high pH, so that is something you probably do want to look into, but rather than buying a pH meter, which can be costly and requires maintenance, why not just go to a pet store and buy test strips for aquaria and use vinegar, as suggested, for correction.

The level of calcium in the water would not cause an issue if you used a fertilizer formula containing more.

[Roberta]

Originally Posted by Ray

If you look at a recent water quality report for San Francisco, you'll note that the alkalinity and TDS is relatively low, suggesting no real need for an RO system (says someone who sells them...).

I

Bit of California geography... San Francisco water is fantastic. People grow Masdevallias and Den cuthbertsonii and other "picky" plants very well with tap water.
However, San Fernando in southern California (located in the valley of the same name), not so much. How much "not so much" needs to be tested, but the question is whether it is 300 ppm water that is tolerable to most orchids except the picky ones, or 600-800 ppm (or worse) water that needs to be cleaned up with RO for practically everything. Merely "bad" or "seriously awful"?

[Ray]

OK. Where in HELL did I get the idea the OP was in the SFO area?????

[Dollythehun]

Perhaps you mistook Southern California for San Francisco? They both start with S...

[Orchid Whisperer]

Originally Posted by Ray

OK. Where in HELL did I get the idea the OP was in the SFO area?????

Ray, do like Bugs Bunny. Blame it on the pesky beavers. Works for me!

[Roberta]

Originally Posted by Ray

OK. Where in HELL did I get the idea the OP was in the SFO area?????

San Francisco and San Fernando share some letters...both are saints, and names start with "F"...

[Ray]

I've spent WAY too much time out there to make geographic mistakes like that. I'm blaming it on the fact that I hadn't finished that first cup of coffee yet.