The Salvini killed the cories I'd kept with them. Maybe other cichlids aren't quite so mean.
I keep earth eaters with cories, and loaches. So far, no unfortunate incidents. All the tank inhabitants keep the bottom stired up. Also, I cover the filter intakes (with a sponge filter or a powerhead cage) and keep them low to the sand. As soon as anything gets stirred up, it goes right to the filter intake.
If you vacuum with a python hose, but a bucket in the sink under the python outflow. This way, when you accidentally vacuum up the sand (don't worry, we all do), it goes into the bucket. It won't clog your drain, and when you're finished, you can just dump it back in the tank.
Glad you like the pool filter sand. Two to three inches sounds about right. If you don't have Malawis or Tanganyikans, throw some blackworms on the sand bed. They'll burrow into it, and keep it clean. Same with Maylasian spiral snails--only they overpopulate, and there's no getting rid of them.