Last week she started lightly fading yellow on a f...

Hello right !! Nitrogen deficence try to fed her with good nutrient which have good proportion of nitrogen or take a mono composant like Canna nutrient nitrogen. Good luck. Peace

Hi there Mael , yeah so you're right about N-related issues. you can tell from the yellowing starting with the oldest leafs first. The plant is cannabalising itself for N. It's a deficiency because you're only adding N with "other" things like in the calmag and so on. usually you do want to keep adding N even in flower , just careful with the NPK you want to keep it going for flowering so something like 2-4-4 , the main idea being twice the PK as the N. If you dont fix it it will get worse, but if you do the problem should stop spreading and it will be smooth sailing from there on. Hope this helps ! 🚀

human urine diluted is a great quuck nitrogen boost.

If it were me i would treat that as a lack of nitrogen...