My 3 month old pit puppy is way to rough with 1 yr old pit?

I asked about this before and was told that Sheba my 1 yr old staffordshire would let the puppy know when too much was enough. Well since then my Sheba has scabs on the side of her body, a somewhat deep scratch on her neck and had a puncture by her eye that now has turned up with Sheba having a red flakey dry ring around her eye. Sadie (the 3 month old) bites and I pop her on the nose until she stops and when it gets to rough I try to break them up but they continue rough housing. The puppy has NEVER had a scratch on her as Sheba is very very submissive as I think Sadie is very dominant. How can I fix this what steps do I need to take because I dont want this to end up Sadie kicking Shebas every time over a toy, bone, love or just because.