Boiler Cleaning

Based off the recommendations over received I will be draining the boiler, wand cleaning followed by a skim. I already skimmed once prior to as well then fired the boiler. Water is much cleaner but still surges. My question is when I drain and refill should I add some surgemaster while it is empty per the products recommendation or should I only put water in the boiler? Trying to make sure I dont have to do this multiple times and get as dry steam as possible. Thanks.