a plant that size needs around 30-50 ml per day,
and your medium dont look optimal for the plant wich soil is it=?
girl looks yellow, that means a) she cant absobt the nutrients in the soil because of wrong ph
the soil has no nutrients...... but normally all soils are fertilised
after having more answers we can talk again
so chekt the brand of your medium, water less, dig her soil around, and give her arflow... and more licht, because she grows leggy
@Mrs_Larimar, thanks for your tips :) the soil is some kind of eco-friendly mixture from the local garden center, is says to have the right nutrients and ph... I added more soil and a fan after I read your response to my question. I think she already looks a lot healthier. Thanks again mate