Your crops BUDS look ok....Although ANY deficiency will show in your leaves 1st....any imbalance will effect the outcome, even if minor.....yeah, a 5L pot supports about a large plantlet....I grew in pots that size once, but each sat in a cutout in a foiled foam board, which covered a plastic lined 2x4 frame that ALWAYS had 2 inches of water in it..the water was HIGHLY circulated by pumps I added...I dubbed it, shallow water culture sys..(SWC)..since they always had access to water, a decent size plant could grow in that size container....With a DTW thats pushing the limits, and isn't why your watering Twice a day....BUT, that frequent of waterings SHOULD keep your #'s more stable than if using 3-5 gallon and watering every 2-3 days....are you using tap water?...I never use RO water....Tap works better for me.... Municipal tap in this region runs about 180ppm, which is fine and contains calcium already...Calmag issue are uncommon is your starting with a quality nute....I HAVE NEVER had a calmag issue using DynaGro (or their bloom formula)..They make some but is targeted toward RO water users....Back in the day, when nutes were not nearly as well balanced, a tbsp of epsom salts fixed it every time (magnesium sulfate)....make sure your ppms are supporting mature plants...If so, most quality nutes will give your plants everything they need....I run my pH at 5.7...PERFECT # for DTW soilless mixes....When that pH is tuned, your plants WILL gobble up the nutes, and show it with lush, green, blemish free leaves...
If you are using RO water, add the calmag....Your RIGHT THERE cause they are far from hurting....A little tuning is all thats needed...YT...