I don't know about snowballs since technically the white is caused by "lack" of color, however I know in my neos astaxanthin caused bad colors to happen. I have recently been feeding the new omniapro because it has no astaxanthin, and things have been working well. The old omniapro has astaxanthin though, so whomever you buy it from- be sure to ask if it has it listed in the ingredients or not.
I used to think spirulina dulled the color of my shrimp, however recent trials have not shown that for me.