Water reflecting abyss?

[DeAngelo]

OK, you know that weird trailing effect you get if at any point in your level the player can see the "abyss" (meaning the nothingness at the edge of a map)

Well I'm getting that effect on my water for some reason. I can't figure out why other than the water not reflecting the ceiling and instead reflecting the abyss. I tried putting black planes outside my level and that fixes it but it oddly causes my framerate to freeze up to about 1 frame per 10 seconds and cause objects to randomly fly around. Freaky. Anyway here's a screenshot.

Spoiler below!