Sump Question

I recently just set up a sump and had a couple questions...

Ok, for starters I put a couple of holes in the inflow tube coming from the sump pump so that if the power went off the back flow wouldn't drain my tank into the sump.

What happens when the power comes BACK on after being off?? The U tube which is draining water into the sump would have lost its suction when the power went off right? Which means when the power comes back on it will not be able to return water to the sump, thus the tank would overflow? How do I prevent this from happening??

thanks
~d

I COULD rig a smaller pump that has a small intake hooked to the top of the U TUBE. When the system is working the smaller pump would be taking water, and I could use it as "current" for the tank critters. When the power goes out the small pump would too, when power comes on it would suck the air out (some pumps will not work with any air in the system however). This any good?

Yeah this might be a problem for me. The power would only have to go out for about 5 minutes for this to happen. I might be able to rig up a switch that turns the pump off when the water gets too high in the sump.

If the power goes off, the sump will fill with water until the siphon breaks. If I put a switch that turns the pump off when the water gets too high it should prevent the pump from turning back on. The pump would already be off, and I doubt the switch would work without power on, but it should disconect power to the pump as soon as it is restored. There must be a relatively cheap and simple switch I could install. I know they make them for septic tanks but they are quite large.
The system would remain off until I restore the siphon and turn on the pump. Its not quite as good a drilled tank but it will have to do for me.
Let me know if this sounds feasable, or if you see a problem with this scenario.
thanks
~d

So far all I have found are ones that turn ON pumps. There must be one somewhere that breaks the circuit and thus, turns the pump off. Though I can't think of any practical reason for making one of these other than this. I COULD do it myself but I would be too scared I wouldn't waterproof it correctly and have a little "accident".

Most switches are simple floats with an internal switches that turn on or off by the float's position in the water. They have a cord which "piggy backs" the cord to the pump. Does anyone think I could take the line from the float and reverse it? The cord going to the float is attached to it on one side, if I wound the cord back to the other side of the float and secured it with a zip tie, wouldn't the switch essentially be reversed?? I think a lot depends on the sensitivity of the switch. I will go and try to find something at home depot...
I will let you know what I find
~d

I don't know why I didn't think of this before: I just bought a longer U tube. This way the pressure on either end of the U tube equalizes before water runs out of the prefilter box. Seems to work fine!

The U tube before wasn't symmetrical. One end was a little longer than the other (measuring from the middle of the U) The shorter end was just long enough to be under water in the housing BEHIND the tank. When the water level dropped in the prefilter box (portion IN the tank) it never balanced without sucking in air from the shorter portion of the U tube. I'm still not totally sure how this happens but it did. I would have thought the pressure in one end of the U tube would have slowly become equal to the other end. Anyway, the longer U tube makes sure there is plenty of water above the ends of the tube.

Does this make sense at all?