Pointe des feuilles devient jaune

Looks like she's hungry for potassium but isn't deficient in it yet, the suggested feeding for the algae nutrient your using is 4ml/l or something like that and your using one. I also see a leaf curling upwards which could indicate nutrient burn, but I only see on leaf tip curling up so I don't think that's the case. They overall look healthy so I would not worry about the tips like that and keep doing what you are untill you can see anything else change.