Plant health - Leaf indicator

Hey guys!

I’m on the 7th week of my grow and everything was going good. I was giving pH perfect (Micro-bloom-grow) as instructed once a week, whilst watering as required with filtered water (pH 6.0-6.8).

I started noticing discoloration on the lower fan leaves and other newly developing branches. I’ve uploaded the pictures. Can you help me figure out what’s wrong and how to fix it?

Are you adding calmag? What kind of water are you using?

I’m using filtered tap water.

I checked the pH of tap water.

Before Filtration - 7.8
After Filtration - 6.9

I’m adding pH perfect nutrients once a week.