Leaf color

First of all, I'm assuming this isn't the first week of your grow nor that your daytime temps are only at 50 - you can easily go back in and correct/edit your diary ... but to get to why your leaves are turning yellow, this looks to me to be a classic potassium deficiency! It's a little puzzling because your bloom nutes SHOULD be giving them the potassium they need. Since they're not, you should definitely try some banana tea (just soak some skins in water for a couple of hours, strain and then use that water in your feed/water) as this will give them a good shot of that micronutrient! You could also try a foliar spray that will immediately get the required nutes into her.... I would recommend FOOP - just mist all the leaves right before or within 15 minutes of lights out. Good luck with your grow!