I have the vinyl adhesive tiles in my tank and have them stuck to the bottom of the glass. I have no problems with fumes or vapors and my leo doesn't seem to dislike it or seemed stressed by them at all. When you consider most UTH don't go over 110 degrees then it's like holding your hand in the same place for a very long time (if you had a high fever). You're not melting any glue to the point of sending off fumes. Adhesive for carpet seam tape takes an iron of 120-140 degrees to melt that glue so I think you're good. When I put my tank together I made sure to put the tiles in first with my UTH and 75 watt infrared on for a couple days to make sure there was no chance of fumes and to get a good stick. The tank temp got up to 108-110 and no fumes. If you want to be safe make sure to use HIGH end vinyl tiles. There's some pix of my tank in my user profile photo album if you want an idea of what it looks like.