It's dry erase. Because the tank is at work, I've had to also posts "don't feed the fish" signs. I had an incident in my first tank where someone "helped" me and f'd up the tank with rotting un-eaten food over a weekend.
Ended up with the betta getting finrot. fun times. This tank, they can't easily feed the fish, and I've since then moved all my supplies into a little cart.
So, the name written is mostly for people who walk by.
Yeah, pretty much the substrate as is, had to work with what I had. And I didn't want to waste it. What'll likely do is once I get something else, I'll switch it out and stuff some of the gravel in a nylon stocking to sit in the tank for a week. I'm pretty sure most of my bacteria colonies are in the filter and biowheel, but I don't discount the ones in the gravel currently.
Besides, I hear sand is much easier to clean come water change time.