Grit stone is a form of sandstone. You're also going to need something a lot stronger than vinegar to test rocks for fizzing. Limescale cleaner works well.
You may want to get that dracnea out of the left side of the tank. It isn't aquatic and won't flourish.
Otherwise I like the layout. I might have considered grouping a few more together to get more of a statement feature, with a few caves for the fish to play in, that way you could have open space as a contrast, but for balance it's not bad.
You may want to get that dracnea out of the left side of the tank. It isn't aquatic and won't flourish.
Otherwise I like the layout. I might have considered grouping a few more together to get more of a statement feature, with a few caves for the fish to play in, that way you could have open space as a contrast, but for balance it's not bad.