I test the grapefrruit before and after. I'm a pp ppm testing fool, I HAVE TO KNOW!!

That's the problem, they aren't growing fine. I keep getting hard purple stems and rust spots and fan leaves doing a corkscrew dance. I get a high 5 pH but fert at 6.5 -6.8 and keep it between 700-800ppm every two weeks. Maybe i give too much, about 1qt every feed in a 1-1/2gal pot. I start with 008ppm water, add cal-mag to 250ppm, add fert to total 700-800 ppm.