I would test each one out in a tub or in the sink in the water depth you want and see how it works. Use that to base your choice on. You could put a piece of string in the pipes to pull the cords up with once the foaming is done. Having them in the tank while foaming could lead to an accidental foam on the electrical devices.

Any kind of string will work. Then just tie the string to the cord and pull it up. Easy peazy