Fresh water tank indicator problems?

[jetlag]

My water tank indicates 3/4 and I'm pretty certain that it is near empty. I've owned the boat two years and it has always seemed pretty accurate however now there is definitely air in the lines as if the water level is low but the indicator doesn't go below 3/4. Any ideas? Can the pickup tube, inside the tank, be cracked or have a loose connection where it is picking up air while the tank still has a lot of water in it? My next move is to pump it all out and see how much I get and what the gauge shows. Any suggestions will be appreciated.

Jetlag
2007 44DB

 

[wetpaint]

maybe over the winter the gauge now reads how much water you have used in lieu of how much you have left...Just a random thought.....more mudslides pleasee

 

[tbirdvet]

Why not try to add water to the tank and see how much it takes to get a better idea how full it is. I guess you could be pulling air. Did you check inlet fitting at the pump?

 

[boatmailster]

clean and if doesn't help replace sender

 

[jetlag]

I guess I could get a flowmeter and check it out. Then try to get to the sending unit. The fresh water tank is under the guest bed.
Thanks