WoW I feel for you on this... at this size as well. I left my friend in charge of my aquarium when I went to Brasil for a month. I told him what to do, showed him how to do it but he did not even add RO water to the tank for over a month. When the neighbours under my apartment complained about the two return pumps running dry and making machine gun sounds on the floor he switched it off. Well the sump equipment anyway. He also neglected to water a 70 year old bonsai for a month. Im glad I had powerheads connected on a seperate supply or I would have lost all the fish as well. On the plus side it was very green and lush on the inside when I cleared the algae from the glass. We learn, we grow and we conquer!
