Reflection opacaty.

Hello all.

I'm somewhat new to SP. I'm having issues with something and thought I'd asked here. I don't know if this is a limitation with SP or with PBR in general. So I have my roughness tuned down all the way so my reflection are sharp. What I'm trying to do is turn down my reflection a bit, or have the diffuse come through a bit more. I've played with the layer opacity with the roughness selected and it just turns the roughness up. I'v tryed playing with the reflection, spec level layer option and nothing seems to be working. 

Any help whit this?
           Thanks.