Hello. I was just wondering if these would be great to keep your tank running during a power outage. The one I have for my PC is in the 800W range and it will run my PC for about 18 minutes after power is out, long enough to close down without losing any data. If my pumps and other possible accessories (minus lights) are only drawing say 100w total, does that mean an 800W power backup would run my system for quite awhile? How long would it run just an air stone pump, days long maybe? Thanks for any opinions on this. These backups in the 200w range are very cheap.