It looks like stalite. I use that with some of my orchids. Did you by chance buy your plant from Odoms? I know they use that almost exclusively on their Catts.

I wouldn't worry about it. I like it and never had a problem.

"Stalite Slate is an all natural medium mined in the United States from
volcanic slate which is then rotary kiln fired to over 2000 degrees.
The material is then made into sterile granules or pieces that are
extremely porous and PH neutral. It has the ability to aerate and also
hold moisture/nutrients for orchid roots to seek. Because it is
essentially a type of lightweight rock, it is extremely durable, and
will not compress. It has low absorption yet the pores store vital
moisture and nutrients for uptake."

Jane

Thanks both of you! I got it at the Fruitville Road Nursery - it was one of the only ones in that mix, so maybe they got it from Odoms.

So either way, I should water every day?

Show a picture of the whole plant...

Only water when the roots look dry. This time of year, you don't want to water every day. I'm in Sarasota and pretty much let rain water the plants. Growth is slow now and the night temps are dropping. You want your plants to stay on the dryer side.

Where in Florida are you?

Jane

I'm in Coral Springs, Broward County. I used to live in Sarasota, actually. Since I've gotten it it's gotten rain, and that is about it. I watered once or twice when it had been four or five days of heat with no rain, and I have it weak fertilizer once with the rest of my plants.

Here are bigger pictures:

Thanks for your advice!