Medusa

a 4-1-2 ratio for npk is out of balance. This isn't a good base for a fertilizer if using 24-6-12. You'd have to add a shit ton of p and k to get the ratios corrected. You will run into trouble sooner than later if you keep using 4-1-2 npk ratio. in soilless you'll want some conbination of products taht equate to 1-1-2 NPK and 4-2-1 K-Ca-Mg with a ballpark of around 100ppm S. This should be an overal concentration between 1.2-1.5 to start ouat then read plant and adjust. Small adjustments to overall concentration (in total) may be needed as each enviornment is slightly different. Slight adjustments to ratios will be needed, but will not result in lockout or catastrophe.... bit-sized problems that are easily diagnosed and mitigated. these nutes should be 100% soluble and fully chelated/plant-ready nutrients. 1 of the products should contain your trace elements. Hydro/Soilless nutes are what you want. Better products will be ph-buffered and balanced so you don't have to fiddle with pH. with good note taking and patient adjustments from this starting point, fertilization will be very easy thing to do with little thought or concern from you.

The shade of green says how much nitrogen is in the plant. Personally I think you are at a perfect color. Red stems could be wanting more magnesium. A little cal mag on feeds would help . Just if your leaves start getting too deep green then you are pushing nitrogen toxicity.