No...I don't think it'll cause any problems having both. I think lowering your warm side temps will help.
Also, back to your original question...it sounds like you may not be getting the item warm enough...
And...when you say hopper...are you talking mice? If so, that's way to small. The prey item should be slightly larger around than your snake is at its largest point. Or, 10-15% of the snake's weight.