test called scattered light

Good morning. I am carrying out a test in which a potassium chloride solution is added. A solution of purified water is used as a blank and then with potassium chloride three readings are taken at a length of 198nm. Absorbances of 1.8 are obtained, which are very low. The lamps have already been replaced. What could be the cause of the low absorbances?

Equipment: PerkinElmer - LAMBDA 25/35/45