4 yr. old water heater, hooked up to a well, last yr. replaced elements that didn't look that bad. It started tripping the breaker again this week.

I drained it, and removed both elements, they looked allright, but I did lightly sand them to removed some sediment. I also flushed the tank pretty thoroughly. I hooked it back up and breaker turns off after about five minutes.

I did try the reset switch on upper thermostat, and both thermostats are set at medium heat (125F) I checked the ohms with a meter, the meter stayed low. One site said it should move high, another said it should read low. Mine stayed low?!

Last yr. with this problem, we ended up replacing the breaker, thermostats, and elements, only to find the wiring shorted out from the breaker to the heater. That looks OK. But should I replace the elements and breaker again?

I have a few questions. First you shouldn't be having issues with breakers and feeder wires, at least in the frequency you are mentioning if they are properly sized and installed. What size of wire is feeding your water heater? What size of breaker are you using? What is the wattage of each of your heating elements. Were you having issues with no hot water or some hot water, but running out fast? If you want answers we need details. Typically an electric water heater is supplied by a 30 amp 2 pole circuit breaker and the wire size is #10. The standard water heater generally has 2 elements, each of about 4500 watts. I have seen perfectly good looking heating elements that had issues. Normally they show cracked or something.

The meter reading depends on where you place the leads. With the power off, you can place one meter lead on the element and the other on the tank ground. In this case you should read infinite ohms. If you put the meter from one side of the element to the other side, then it should read relatively low ohms somewhere probably around 12 ohms depending on meter and element. That's why you have two conflicting ideas on the readings