Got back today. I left the tank from last Friday at about 12pm until today at about 1PM. My water level dropped 1" (in a 29gal), specific gravity went up from 1.021 to 1.024. All my levels were normal, ph went down a tiny bit. I had my light on a timer and thats about it. The fish looked fine, not skinny at all. I have the temp at about 79º. I probably should have decreased it to 75º to slow the evaporation and also the fish's metabolism.