For those of you that use/have used inline chlorine feeders: should the reservoir be filled with water? Does it fill automatically? Mine seems to only get about an inch or so of water in it, so only the bottom tablet is wet/dissolving. This is a Klor-in brand feeder. This is the second one since I figured the first one was defective because it didn't let any water into the chamber, and the tablets never dissolved in over 3 weeks. Anyone have any experience with these?