Someone please help with diagnosis/cure.

Plants are 3 weeks and 3 days from sprout, grown in happy frog, ocean forest and perlite all equal parts. I have givin them zero nutes and watered one every 3 days with tap water ph'd to 6.3. A week to 10 days ago this started and has done nothng but gotten worse. Temp and humidity is a constant 78 degrees and 40%. Any help would be greatly appreciated, thanks in advance.

Looks like cal/mag deficiency.

Just start feeding her any veg nutes and she will look much better in a few days if not over night. Another thing, start watering more.

Thanks for the lightning quick replys fellas, Im using the ff lineup, so I should juststart there veg schedule? And maybe water everyother day?

Yeah start feeding, using only the Big Bloom at first. Water when you stick your finger in the soil and don't feel moisture. Lift the pot before you water to feel the weight and you will get used to the feel of a thirsty plant.