Well, I hate to tell you this but it's your temp is a little too high. The humidity is fine. If you try to make the area more humid, all that will do it make the room warmer. Superthrive states specifically to give one drop per gallon, unless you have a large need for it. Whether hydro or not, one drop per gallon. Your plant needs ferts. If you have grow big, then I'd give some at least half strength and if there's no calcium or magnesium listed on the bottle, then give a little seperately. You can give fert without a ppm meter. If it says to use a teaspoon per gallon, just give half a teaspoon. I think I understand what you were thinking, that because the leaves feel dry you think that there's not enough humidity in the room and that's the problem? If anything the leaves feel dry because they're not getting enough fert to grow properly. 45% is fine for humidity.