Confusing isn't it... LOL
Aluminum tape works better. Stick onto the pad better and you can take off if need be latter on.
Problem is ..you have duck tape on hand and it works about the same depending on the brand you buy.
But you'll never you foil tape for anything else. LOL
You'll hear latter that you must use aquarium sealant. Why ?? I say
You're not housing fish, just using a fish tank . Using silicone caulk is cheaper, work just fine and can be use for other things.