Well I have never been in one before so I don't know a lot about it. To keep your water temp up wrap the tank it blankets. This will hold the heat in longer. If this still doesn't keep the tank up to the desired temp. You could heat water and place it in bags and let the heat transfer from the warm water to the tank water. Heat energy flows from the warmer object to the cooler so you might need a lot of warm water to accomplish this. Skimmer will be fine off, same with reactors. Just feed light. You need something to keep the water oxygenated. It would be nice to have a generator to keep your powerheads on, but if you can't you might have to stir the water and let some oxygen get in.