May still be recovering from topping... was that recent?
bringing down humidity will increase transpiration... I bet the plant's uptake rate of water impacted by slow transpiration in high humidity. 40-60RH% would be better... if you control environment tightly, look into VPD - at various stages there is an optimal temp/RH%.... othwerwise, i control RH mainly as a preventative measure for microbial growth, regardless of "optimal"... <RH65%.
feeding in coco -- fertilize every time with a 650-750ppm mix. get 10-15% runoff... wait for top layer to change colors when drying and repeat process. always saturate entire pot. always get some runoff waste (down drain or toss outside, do not let it re-absorb) Easy as pie. Want a good breakdown of a well-balanced mix? check out any of my diary weeks. They all include a table of elemental PPM calculated from guaranteed analysis labels.
saturating entire things trains roots to grow deeply instead of superficially. wet-dry cycle is good for pest prevention and avoids crap growing on top of substrate. maintains pH and nutrient content in soil. If you do this religiously, you can pretty much eliminate problems relating to nutrients and irrigation when something arises.