With my false bottom, I have another piece of pvc pipe that runs from the bottom of the tank to a few inches above the substrate level so I can put a tube down to the bottom and syphon out any excess water. Would that work for ventilation?

My hermit crabs are spoiled like you wouldn't believe haha. They basically live in a crab castle. I'm an admin in a crab group, so they are very well taken care of. I have to set a good example :P

Do you keep crabs too?