Yellowing leaves

This is my first grow and I'm trying to be pretty generic for the first time. Still in veg, I'm having leaves turn yellow from the tips and eventually die. This seems to affect the leaves that are older than the newest, but doesn't seem to be starting from the bottom of the plant. Can you help me identify what's going on here?

• Strain: GHS Super Bud and free Seedsman White Widow (same symptoms on both)
• Soil: Nectar for the Gods #4
• RO water with 1 tsp cal-mag per gallon
• GH Flora series, using the aggressive vegetative growth at half strength which results at 750-775ppm
• Water pH 6.4-6.6
• Watering ever few days when pots are light. Feed, water, water, feed.
• 315 watt CMH
• Temps 75-80 F, RH ~65%

Thanks!

I would go much heavier on feed up to 950 ( ish ) .
Medium is pretty basic in nutes. So plant will need whats missing thru a bigger feed. Ro water isn’t necessary as bone meal provides the calcium. Plus municipal ( city water ) has both cal and mag. Tap water works with any bagged soil medium.

Basically they are hungry.

Thanks. I was afraid of burning them but I will start feeding them more today and see how they react.