I was doing a water change and the lid to my HOB filter was off. My gf looked and thought the algae growing on the slopes back into the tank was gross and decied to see what it felt like. Right about the time her finger got to it I tensed up and said DONT DO THAT!! but alas i was too late. She wiped across the clumps of algae and broke loose huge chunks that went spilling into my freshly cleaned and refilled tank.....

But I geuss really I should just keep my filters cleaner.