[Simons]

I have noticed many people commenting on the 'just essential' equipment during a power outage. I think most would put their return pumps into that category but I disagree.

I do believe it is important and it is something I have planned for but it isn't the most essential, at least not in my set up. I do not have a high rate of water running through my sump, primarily because your water volume through the sump should be only as much as your skimmer can handle (assuming you are indeed, running a skimmer). I know all the rules of thumb X turnover rate per/hour based on the volume of your display tank but skimmers should set that requirement assuming you have an appropriate size skimmer for your needs. So for me, a skimmer is not essential during a power outage and would be difficult to support due to their generally high power load requirements.

Power heads...that's the most important in the power outage, gas exchange is fundamentally the top priority. Tanks can live without dosing, skimming or a 'fuge' for a long time but only hours without good flow.

If you return pump is very large and you are pushing lots of water through your sump then, okay; I can see that being your gas exchange but for tanks similar to mine I would argue that point. 90% of my bio filtration (nitrogen cycle) load is in the tank where 90% of my porous rock is situated. I do have some in my sump but not enough to sustain my tank, so outside of the skimmer and some chemical reactors the sump is secondary to my needs.

I can run for 2 days with no power on my battery backups to the point where, in the winter falling tank temperatures might be the second greatest issue. That is another discussion since heaters draw so much power it wouldn't be feasible on battery backup, it would be generator time for something with that kind of load.

Sorry, just my 2 cents on essentials. I know everyone's tank is different but generally I would say most tanks I have seen the sump is never the primary concern in a power outage.