A few years ago when we were starting our first reef tank my wife and I picked up a frag of two blue mushrooms. Fast forward to today and we have WAY more blue mushrooms than we need in our tank. A few of these are on random pieces of rubble that can be pulled out of the tank and dealt with but quite a few are attached to the base rock that cannot be removed. How do we kill off some of the mushrooms that are taking over?