Yes you should clean the face of your transducer as algae growth will hinder its performance. Use a soft cloth and mild household detergent to clean the transducer. If the fouling is severe, remove the growth with a green Scotch-Brite pad. Be careful to avoid scratching the transducer's face. Lowrance states that you can also paint the transducer with water-based anti-fouling paint as long as the paint does not contain metallic material.