That's sooo nice, i'm jealous.. I want to make a brackish set up for some mudskippers and I was wondering it your cement mixture was rough or prickly. I know you mixed it with other stuff but I'm trying to come up with the best idea for a muddy look that is smooth.
The cement mixture that we used is rough but not gritty less like cement and more like heavily textured tile. If you were to add another layer or two of epoxy then you could smooth it out nicely because it fills the gaps and valleys of whatever you put it on. I think that would be a good way to go for mud skippers.