First time in coco and autopots. Can't figure out what's wrong.

bottom feeding takes more trial and error. the zone where water absorbs up to is likely to build up minerals over time. If you consistently run into issues later on in a grow, this will definitely be a contributing factor. With this sort of irrigation method, you may need to do a top-down watering occasionally - preferably normal fertigation levels rather than water only, but whatever ends up working best. Definitely stop thinking of calcium and magnesium as the same thing or somehow linked. they are not. They have a set of different symptoms, too. Looks like chlorosis starting tip-in and bottom up, though not overtly... leans toward a N-deficeincy, but maybe lockout or imbalance in nutes causing it is more likely, given the irrigation method. No telling what's built up at the top of that soil where the waterline absorbs up to. Also, you can save some money. floraflex nutes are expensive, but they are made of the same ingredients as everything else. Could calculate ppms and compare, but the method of irrigation makes that less useful N 120-130 vege / 100-110 flower P 40-60 - numerous studies show amping this up does nothing useful K 180ish - See P... amping it up does nothing useful. You merely want to maintain critical levels in substrate Ca 100+ Mg 75ish S 100+ your local tap water will add Ca and Mg maybe even a few ppm of N. So that will be something to consider. Also, this is a low EC formula, but the ratios are good. Depending on local vpd and co2 etc etc, you may need a higher concnetration than this, but at similar proportions. If you have similar (does not have to be exact) proportions that makes me even more confident that it is the method of irrigation is the cause. the fact you don't get runoff is the problem. you are bound to have various buidlups of minerals in that substrate. You may need to run a gallon or two of water-only through the top, see how it reacts then resume fertilization through bottom feeding if all is well or it shows a hint of deficiency afterward. Runoff is essential to soilless growing. It maintains an equilibrium of nutes in the substrate. Impossble to have a buildup of minerals in the substrate -- can still overfeed the plant obviously. but, one less thing to rule out when diagnosing.