Just replying to my thread here for anyone curious about using the Water Guru. So my old water guru died and I upgraded the new sense 1. It has an improved battery storage area, unlike the older version which on a couple occasions popped open leaving the batteries in the skimmer for days (pretty bad design flaw). My work around for burning through cassettes is to just leave an old cassette in the machine through the winter. They also suggest removing the device entirely and taking batteries out, but I leave it in over the winter to monitor the flow and temperature which doesn't require using up the cassette. Yes it does use up batteries, but without the cassette in taking daily measurements it uses very little battery through the winter months.