Water tank senders are a complete waste of time, energy and money. Get a Watercounter and know exactly how much water has come out of the tank.
It would be nice to know for sure what was in the holding tank though.
Did you correct the issue with the 3/4 full lights? I know a "real gauge" is better but I have found the 3/4 lights to be perfectly adequate for us and it's already there and fairly bulletproof.
Pate, if the tank is fiberglass and you can access one side, you can install a gauge on the outside with a self stick tape and it reads to a gauge with lights for different levels. Had it on the trawler and it worked fine. Snake River used to make these and recently I heard there is another source.
Bob
Magnawake, is it just the actuator that is bad? If so I have a pressure sensor that will replace it.
My actuator was unstable and I was never sure of the fluid level of my tank. I installed the sensor and now all's well again. I have extra ones on hand and you can have one if you like, (no charge). It is very sensitive and blinks at every pulse of the pump, and will stay on permanently once the tank is 3/4 full. Let me know if you want it. Ron