I let the algae grow on the bottom. Eventually, it can/will get covered with coralline and if a frag falls on it then it will encrust quickly. It might take a year, but I like the look when a tank has a crustose bottom.
Cleaning; I'd blast it with a powerhead to put the sand & dirt into the water where it will go into the overflow (and a sock) or push the gunk into a corner where you can siphon it out.
To keep your hands out of the tank, get a long fiberglass handled scraper. I like the plastic blades, but people use metal blades on glass and they work pretty good but with any scraper you need to be careful. If you don't want a long handle, then credit cards and old hotel keys work pretty well. I trust you have used a Magic Eraser pad. GL
Oh,and the tank looks nice!