Stonerdanswered grow question 4 years ago I believe It's a slight Potassium (K) deficiency - Yellowing tips and margins with slight chlorosis and mottling/blotching.
Increase your Potassium output (usually in high concentrations in "bloom" fertilizers) and lower your Cal-Mag usage to 0.5ml/l max, those are micro-nutrients needed in small amounts and constant feeding of it will cause a toxicity! (Calcium toxicity inhibits Potassium uptake so it might be an option as well).
Hope this helps! Good luck and happy growing :)