The higher the water level in the tank gets, the faster it will run out the bulkhead. If the water level gets above the bulkhead, which it very well could, then you can get an air lock issue. I've seen pics where people would drill a hole in the pipe, right where it comes out of the bulkhead, use a threading tool and add threads to the hole, then install a John Guest valve so you can let air into/out of the pipe. That keeps the flow steady and quiet.