First Grow - RQS Watermelon/RQS Critical

Starting to get my first issues with what appears to be calcium deficiency and perhaps nitrogen deficiency as well. Bumped up the CALiMAGic to 2mL per gallon to try and turn it around. Measured runoff ph is 6.15 so I think still ok. Did not get a PPM measurement yet though. Assume I still have a few solid weeks of flowering to go.