I agree with 2 pumps, fused on two different circuits. You don't want to blow one fuse and lose both pumps. I use a 2000 and 1000. The 1000 was one I had laying around and put it in as the front pump, with the 2000 in the back. If I had to buy it, I probably would have gone with another 2000. Both have float switches with manual override.
Pumps are on separate circuits, both with separate Auto/Manual on-off-on switches, separate circuit breakers, and indicator lights. Both pumps are left in the "Auto" position unless there is a good reason not to...
Like others, "been there, done that" with pumps. The float stuck and I did not notice it while fishing in some rough water. Really did not know how much water was in the bilge until I tried to head in - the boat was SO SLOW to plane...

Checked the bilge and, damn was there a LOT of water in there!

Switched the pump to manual and (good news) the pump came back on and pumped like a SOB for a long time! Here were my lessons learned:
1. Captive floats should not be relied on - see Jones comment on testing ability - solution: new float switch that is easy to get to.
2. No back up to single pump - solution: 2nd pump on separate circuit to eliminate single fault failure
3. You really need to pay attention to the caulking in the splashwell on CCPs. The water in the bilge was coming through the seams in the spashwell. It was a bit rough that day, with a good deal of water coming into the spashwell. I found out the hard way that a good deal was also going into the bilge. Solution: a bead of 5200 on all the seams in the spashwell - almost zero water in the bilge since then.
