I bought the Tunze 5017 for my 40g after using a nano tunze for years that finally wore out. I love the additional features, like the glass sensor and high level float valve, but I’m having a problem I can’t figure out. Since my tank is on the smaller side, I adjusted the internal switch to “nano”, as initially it was dumping too much rodi into the tank. My problem is when I use “feed” mode on my apex when the feed mode is done. I have the skimmer and ato programmed to come on a few minutes after the return pump comes on so the water level in the sump can lower to normal levels. When the ato comes back on, the “low” light and beep always sounds, even if the glass sensor is totally covered with water. This has resulted in a gradual lowering of my salinity. Today I held a measuring cup under the ato tube after a feed cycle and it ran a full cup of water into the measuring cup before shutting off. Since none of that water actually went into the tank, my guess is that the ato is somehow programmed to run for a certain amount of time upon startup, regardless of what the sensor says. I use the feed mode daily, so this is a real problem. Has anyone else had a problem like this with the 5017? Any help is greatly appreciated!!!