I agree, the conduit is designed to flood with water. The problem is, my pool is not to code. The electrical box where the electrical connections are made is supposed to be elevated above ground level (I'm not sure what the specified distance is). On my pool the box is embedded in the concrete at ground level. So I've got to seal that sucker up good from all directions to make sure no water gets in.

I ended up using expanding foam to fill the large gap around the wiring then covering that with a generous portion of silicone caulk. I did this at both ends of the conduit (in the light well and in the electrical box). My pool is refilling now. The water is above the lights and they are still working. The next test will be the first rainfall to see if the boxes (there is one for each light) were sealed well enough.