So I have a white dog, and a mostly white Merle dog. I need a shampoo to keep the whites, white. I haven't had time to groom Kobe in a long time (been using a groomer). But now that I have time, I want to do it myself. What do you guys use? I need something that's very mild, but hopefully good for whites. I use EZ-Groom Crystal White Shampoo. But, I recall it was somewhat harsh. I only used it on his ears. Any suggestions?