Keeping cats off my snakes tank?

[Pogie]

Ok I have 4 cats, 2 of which will refuse to stay off the Tyrion's tank. I have a heavy piece of old fridge (wire) shelf setting on top of it. One of the cats will just lay up there, the other however tries to claw his way into the cage. No they are not declawed. I have a water bottle by me at all times and I've used the wide clear packing tape to no avail. I put so much tape on it one night when I got up the next morning the top of the tank looked like a living mammal on the top. The darn cats just walk on it like it's nothing lol. I'm running out of options and have no idea how to stop the lil sapsuckers from getting on the tank!

If they see me with the water bottle they run. But as soon as I put it down the race is on to see who gets back up there first rotfl.