I have three Koralia Evos on my tank; they are new, as I've only had them for about a month or so. Tonight I came home from a movie and one of them was working normally, but the other two were working in reverse (sucking from where they should be blowing). I took them apart, put them back together again, and after a few tries of doing that, they started blowing from where they should. I'm confused. What is happening?