Lowrance elite 4 hdi temp gauge issues

[Flyak13]

So I'm having an issue with the temp reading . It's reading 10-20 degrees over actual temperature.... This is my second transducer on this unit and I happend to me once before... I thought the first time because I had left it out in the sun but made sure to take extra care of this one.... I have a warranty but just don't want to be stuck with out a ff for who knows how long. Has anyone else experiences this ? How'd you fix the problem and what can I do to prevent this from happening again? Thanks