Root Problems in S/H brown spots.

[GinaStarSeed]

Hello. I am new to orchid growing and need some help from more experienced growers. I switched around 25 orchids to S/H over a month ago. They had some yellowing leaves at first but most seem to have adjusted alright. A few still have yellowing leaves sometimes. Also some of them had old puesdobulbs that just totally rotted.. not sure if that is normal. Anyways, I unpottws two to see how the roots were doing. The one I will show in the photo literally had zero roots left. I cut them all off and potted it in S/H. Also, I have had a layer of spagnum moss on the top of the pellets to help with moisture. Should I leave it or remove it after new roots start? It has a ton of new root growth and a new top growth that is 4in tall: the thing is that the roots are pretty white and most of the tips are yellow not green.: and the worst part is they have these brown spots all over them. Almost like something pressed up against them and made them start to rot a little there. Nothing too big or mushy but all the roots are covered with the brown spots on big orchids I uprooted to check on. Only a couple tips were gone and kind of black st the very top of the root. The roots are a bit translucent also. The orchid in the photos is a gamma orchid , the large ones with the giraffe like spots in the flowers. New to orchids and really love them. Hope someone can help.