Tape is fine to use outside the tank....never inside....it's not a pretty sight when they get stuck to the tape...
Scotch tape in my mind, wouldn't work all that well...but thats just me...I use packing tape. It works quite well. Get heavy duty. Don't use aluminum tape, it conducts heat too well, and will give false readings. I don't like electrical tape either, because it doesn't stand well to heat.