Using visqueen as a pond liner 5m diameter. What type of tape would be most suitable to ensure its waterproof?

I intend using 2 layers of visqueen at right angles to each other. I need the tape to hold the plastic together and be waterproof. I am sandy landUsing visqueen as a pond liner 5m diameter. What type of tape would be most suitable to ensure its waterproof?
Grey tape, you can buy it with your visqueen, plumbers,concretors all trades use it , it sticks like s#*t to a blanket. Make sure when you fold the plastic over to get your circle you tape the folds as well. Also don't forget to leave enough overhang around the top so when you fill water it will settle and pull some in of the top sides. Not like me first time, cut plastic and water filled and plastic finished up under the water level...dddaaahhh.Using visqueen as a pond liner 5m diameter. What type of tape would be most suitable to ensure its waterproof?
personally i would use a rubber liner...sunlight breaks down visqueen . i try to save it from year to year for covering concrete pours and by the second or third year its worthless...