Are all the Magnets $14.99 or is there different sizes? I'd like to pick some up to mount corals to the back glass of a few tanks. I currently do this with the Vertex cleaner magnets sealed in acrylic as well. They're just not that powerful. Once the coral grows out a bit they wont hold as well. They do work well for encrusting corals -Monti's,Pavaona,Cyphastrea.