Dunno about that one - never used that one before... Some of us use "Keep Alive" tanks with various aeration systems. The fellow that develops them has twaeked and tweaked for the best bait keeping solutions...
Herring pose a couple problems. They build ammonia quick and they lose their scales quick. Many pickup filters screen out the scales but get clogged quickly and fail that way. Some allow too many scales to pass the pump screen and this wears away the motor/pump fins. Any wear of pump or loss in effective airation will most likely cause your herring to go quickly.
Keep alives also have several different airation systems. Some normal water/air pushers and some are better just air pushers. They also come in different styles (I'll let Saltheart comment on those because he knows them better)...
As far as power, I went to Benny's picked up a cheap, $6 10ft - 12V auto extension cord cut the end furthest from the cig adapter and spliced them into the power source for the motor. I have a couple outlets in my truck and I can run it no problem. Just make sure you have a good battery charge before going to bed at nite (I once woke up late and didn't check til late morning - had to jumpstart truck).
Keeping herring is by far better with a tank with rounded edges. Sharp 90deg edges like a cooler will cause this fish to swim into and hang in the cooler which kills them a lot quicker - not sure why. 50Qts is also pretty small only 12.5Gal and figure about 8 because you can't possibly fill it up. I use a 35Gal (140QT) rounded Keep alive tank. I've used coolers before and they just don't last as long.
"Keep Alives" are not cheap but the Sportsman's Den usually has them at a good price at the MSBA show in March and M&D's carries them too. It is tough to drop this kinda coin on a herring tank - about $150
http://www.capecodtackle.com/Merchan...8_00_MISC+MISC
Anyone know of any good sources for the rounded tank itself?