Are you adding the rock into a new system or old system? I like to use a big box store 20 gallon container or brute trashcan with;
Salt water at 1.025, a heater, and pump.
If you live in a cold climate you can double up the bins for insulation.
If you wanted to etch it clean you could soak it in muriatic acid / water, be careful and use Ppe.
If you just wanted to kill anything living, bleach and water will work.
I’d avoid glue as well. Using cement is good, as is using acrylic or other plastic rods drilled through the rock. Epoxy and rockwork is kinda hit and miss, though does work.