Sealing a power cord

[pweissma]

I'm building a nilson/kalk reactor. For mixing, instead of running a pump on the outside of the container, I'll put a small powerhead inside the container. My plan is to run the powercord through a short piece of 1/4" pvc and seal it in the container with a 1/4" Uniseal. Still I need to seal the space between the powercord and the inside of the pvc. Is there some kind of resin I could use. The only thing I can think of is silicone.