Mike, your Mak 4 draws about 1 amp at 120 V, but around 10 amps from the 12V gel cell. Plus your inverter (depending on type) may not work below about a 50% charge on the gel cell. (Deep cycle batteries are damaged when discharged below 50%). So your 48 AH battery really has about a 20-25 AH usable capacity, which would translate to about 2 hours for your return pump.
I'd think your backup capacity would be much better put to use running a powerhead in the display tank, rather than moving water all the way up from the basement, especially since there will be no heat or skimming down there when the power's out. A powerhead in the tank directed at the surface will keep things moving, aerated, and the display will probably lose less heat than the basement sump.
Focus, sorry you lost so much.I know it is a real downer.
Why not run an extension cord down to the basement for a powerhead?
We use essential cookies to make this site work, and optional cookies to enhance your experience.