underscorebass2

I know this might sound stupid and I'm sorry if it's been posted before, I tried searching it, but I just got back from the pet store a couple hours ago with my betta's new 2.5 gal. acrylic tank, and my Whisper 3i's suction cups won't stick to the tank for more than 20 minutes before floating around the tank. I don't understand because my thermometer and heater are fine but the suction is just not happening with that filter. Any ideas besides putting gorilla glue on the thing to hold it in my tank? Any help is appreciated.

Butterfly

Some suction cups have to get warm before the soften up and stick, some never stick (sorry) .
Is that the filter that has the little hook on top? If so the hook will be enough.
anyway welcome to FishLore
Carol