Turns out It was a ph issue. I took the other two cubes that won't give me any love and squeezed out the water, tested the ph and it was 8! Wtf! I guess I need to be a bit more paranoid in the future when using rockwool and take my time. So.. I set the cubes on a paper towel and this evening ill give them say a 5 second dunk 1/3rd up the cube unless anyone has a better idea, I figured id let the rockwool wick up what it needs. Plain ro water phd to 5.5 is the plan.