"Bill Stock" wrote in message
...
I looked at the Inverter/Battery setup, but many of the inverters put out
POOR waveforms, which are detrimental to many powerheads. The UPS
I bought has a fairly good reputation for a 'cleaner' sinewave. Although I
may still go this route for powering up the fridge/freezer for longer
blackouts.

I would not be concerned with sine/square wave...
I would check if this UPS can be used for the heater at all.
Most of UPSes I know do not let you turn on the device when on battery mode.
OR, they turn themselves off when detect a no load situation on battery
mode.
And this might be a problem because your heater will work in on/off mode...

I would avoid puting heaters/lights on backup power.
They are not needed in emergency situations.
Water circulation/gasses exchange is much more important.