New Vevor bucket system - air stones not bubbling

Hi, I just set up three buckets of an 8 bucket Vevor hydroponic system. Everything looks great but the stones don't seem to be working. I placed them in water for 10 seconds before connecting as instructed, made sure the tubing is all the way up to the neck of the connector of each stone, and placed tubing and closures on the remaining nozzles in case pressure was escaping from the pump that way. I took out a stone from one of the buckets and placed just the tube into the water and got bubbles that way, so I know the tubing isn't blocked, and I blew through the connector of the stone and water did spray so the stone isn't blocked, either. All the parts I'm using came with the system, so I'm not jerry-rigging anything. Is it that it just takes time? This is my first time using this type of system (upgrading from Aerogarden), so please pardon my ignorance. I appreciate patient guidance, thank you.