Preping the tank for a 4 week vacation

[Albertan22]

So I'm getting ready to leave the country for four weeks. I have a good system in place to handle top off water, and I've arranged for a tank sitter that will be able to stop by every 2 to 3 days to check on things, empty the skimmer cup, and feed frozen food. However, I've been debating whether to put on my automatic feeder (feeds flake food twice a day) while I'm gone. My tank is purposefully understocked right now in anticipation of this trip, with only 2 occelaris clowns, 4 chromis, a few corals and the CUC in the DT right now. Will the automatic feeder running for 4 weeks without a water change cause nutrient/algae problems? My fish are used to being fed everyday, and 4 weeks seems like a long time to go only being fed every 2 or 3 days...

Another idea that I've tossing around is maybe putting a heater and several air stones into the DT and powering them from a separate breaker. That way, if the breaker or GFI trips on the regular plug for the tank, I'd at least have heat and oxygen in the tank until my tank sitter arrives and sets things right. These wouldn't be on a GFI though. Would this be a good idea? Am I being paranoid? I've never had problems with triped breakers or GFIs in the past, but better safe than sorry right?