Passindex not working

In my age I have a vast ocean (waveset) with lamps with sprites, and windows with Alpha. Now, When I set the passindex of the window higher than that of the water, it does not change the object under the waveset from bleeding through. I wasn't sure if it had to be higher or lower, so I tried both, but both times it did nothing. The same goes for my sprites. Is it something to do with such a large alpha object? (the waveset reaching to the horizon) Is there some other way to fix this problem?