Put in a float valve just in case you forget to turn off the water. I also drilled my water container near the top and ran a tubing to a drain as a fail safe overflow. Are you using anything to bond your rocks together for your scape? If not consider e-marco cement.
i have a float valve installed both on the mixing container and ATO reservoir. Secondary fail safe is the RO filter itself. It have a build in timer to only run continuously for ~30mins before auto shut down to prevent the pump to overheat. I cannot disable this. Its a 400gph unit, so 30mins is enough for my need.
On the scape, i am using a combination of super glue and reef safe epoxy.