That was going to be my suggestion Alan, Blocking the holes and by-passing the bladder. I can’t see how it would hurt as long as you didn’t play extremely loud/hard? I can’t see the bladders advantage? Unless you are trying to play both ends of the keyboard simultaneously I think your airflow would be as even as it is in any non-bladder melodica? I must add though I’m going by your pictures and description, I don’t own one of these myself nor have I seen one in person.