why are my roots brown

So my plants are about 3 weeks old and I just switched from plain tap water to technafloras starter package cause this is my first grow and it seemed like a good deal so I used boost,grow,thrive alive red,magical and sugar daddy that is the (recipe for success) that came with the nutes but I used all at half strengh to start but it quickley turned my healthy white roots an ugly brown color and not there is a little bit of white foam around the edge of my res so I was wondering if this is at all normal or a bad sign BTW my roots all feel healthy not slimy or anything any advice would be greatly appreciated