I grow Barney's Farm Northen Lights. I am going to adopt your technique of including nutes in every watering, but at half strength.

Well the effects I see happen about 4 weeks into flower. Suddenly the mid-level fans start forming rusty dots in between the veins. It doesn't look like any magnesium deficiency pics I've seen tho...these leaves don't yellow like an N deficiency. The dots spread on the leaves and spread over time mostly up but some down the plant, turning the first leaves affected almost 50% white as time goes on. A week after the dots appear, the leaves near the top start taking on a purple cast which worsens and the leaves go crispy.

My ghetto climate contol keeps temps between 65 at night an about 80 during the day. Plants are 14" from a 400watt Metal Halide.

I feed RO water, supplemented with 1tsp/gallon of 'CalMagMax' as a base for all feedings...with ferts or without. I pH the solution going in to about 6.6pH give or take a point us GH pH UP. I go for enough input solution to produce 2 - 4 cups of runoff from a 12" pot. The run-off pH varies from 5.6 to 4.8.

I'm thinking my soil (Farfard red potting soil) might be too acid? I got some lime for my lawn, I'm considering mixing that in for the next plant. What do you think? I get decent enough yeild but it's sad seeing the plants in week 5 of flower with all the big fan leaves nearly dead and the leaves at the top of the buds (I top twice) all crispy and purple. I'm thinking I'm losing alot of yield.

Any advice appreciated.