deficiency?

Runoff Is ok .... pH 6.5 EC 0.9 I try to increase and EC ??

This chart may help: https://loudclouds.co/wp-content/uploads/2016/07/marijuana-deficiency-chart-jorge-cervantes.jpg

Why no diary so we can see what you've been doing? Impossible to tell you with any kind of accuracy what this is or what might have caused it. Having no information, I'd tell you to flush until the runoff is within a good range - I don't know if you're growing in soil or hydro or what! - but the range for soil would be 6.0-7.8 and for hydro it's 5.5-6.5. You've got some kind of problem there and it usually is attributable to a PH imbalance... so start with the flush and then make sure what you give her is (water/feed) PH balanced. Good luck - and start a diary so when problems/questions come up, we can look at the totality of the grow and help you more accurately!