you can put a glob of super glue on the glass, put the gsp on the glue, then put more glue over a part of the gsp, making sure to connect the glue on the gsp with what's on the glass, and immediately hit it with a spray of tank water with a spritzer. the water instantly sets the glue, and the glue 'bridge' across a part of the gsp sort of latches it onto the glass.