I was out of country, in Europe, for 3 weeks over the holiday break. to make things worse, before this trip I had very little time, so I prepared the tank for my absence in a super rush. I got lucky and most of the equipment ran fine. The corals & fish did great. not only that I didn't loose any, but I can see obvious growth on them. What do you guys do when you have to leave the tanks alone for extended periods of time? Here is what went down in my case - the house was empty for 3 weeks, from Dec 16 rto Jan 6. - a friend had the house key, he planned to stop by 3 times to check the house and water the inside plants. He doesn't know much about reef tanks. In the end, he had to come by one extra time because of a heater failure that I'll explain below. - I have a Reef Keeper that controls the lights, ATO & heater. I can access the RK software over the internet. - I installed a security cam to see the tank. I can also access the cam stream over internet. - I installed an auto feeder for the fish a few weeks in advance and made sure it doesn't overfeed them. I didn't setup any feeder for corals. - I added a 20G box with RO + Kalk water, and used my secondary RK, a float valve and a small pump to be able to feed the main ATO tank from this 20G box as the main one empties. The main ATO tank also holds 20G of water. So combined they had 40G of water, which is enough for 4+ weeks. - I prepared 15G of RO water for my friend with the instructions to fill up the 20G box if it gets near the bottom 5G mark. So that would extend my ATO with another 2 weeks. - I added an acclimation container and hook it to the skimmer's overflow tube. When the skimmer's cup would get too full, the waste will overfill in that container. To prevent an accidental flooding of the floors, the container was hooked on the inside wall of the sump - if it overflows, it would just dump nasty stuff into the sump, probably affecting the tank, but sparing the house. - I left the house heater on 71F just in case. And this might have saved me from that heater failure. - I cleaned the all the pumps and powerheads. Beside the ATO and the skimmer, my tank only has a sump with macro-algae+mangroves refugium and a bio-pellets reactor. Both don't require any often maintenance. Beside the fish auto-feeder, I did most of the work the night & morning before my trip started. You can see my improvisations in the pics . The only failure over these 3 weeks was the heater! Actually, this was the 3rd heater that burned out in my setup in a short period of time, and now I have a strong hunch that my RK outlets are to blame. I had 2 failures with the heaters in Oct-Nov, they were both connected on the RK outlet. So this 3rd heater was connected on a separate outlet initially, it worked fine for weeks, but the day before leaving I switched to my usual RK port that is setup as a temp controller being afraid not to have an overheating situation. The heater was set to 76F and the RK controller was set to shut down the power on that outlet at 79F. Well, about one week in my trip. I get an alert that my tank's temperature is 72F. I saw the email late, when I checked the RK logs, I saw that the temp dropped from 76F 72F for almost 2 days. Then it took a day more until my friend was able to go to the house and fix the problem. Since he had no knowledge, we did an online "session". He was working on the tank while I was seeing him on the security cam & talking with him over skype . He unplugged the heater, found my spare heater in the garage, plugged it into the standalone outlet and set it up at 76F (in the future I need to make sure that my spares are preset - this was a digital Finnex and it took my friend a bit of time to figure out how to adjust the target temp even though I was giving him verbal directions).