You are maybe being too kind to it. My winter night temperatures can go to 4 deg C (40 deg F) or occasionally lower. (Days in the 15-20 deg C range most of of the time) Maybe try leaving it outside except perhaps during the hottest days of summer. Minimize the moving around. Most of the time, outdoors conditions likely are fine.
Another thought... water quality. Sophronitis in general are pretty fussy. I use RO water for them, since I started doing that, my success rate improved. They don't like my "liquid rocks" that come from the tap.
Fertilizer at my house is a "sometime thing" for everybody... I try for every 2 weeks but doesn't always happen, 0.5 g per liter (1/2 teaspoon per gallon)
approximately. I don't do it surgically... I load up a power sprayer with the "soup" and give everything a bath. Done. Maybe less than ideal, but they grow and bloom so I'm not complaining.
Fertilizer at my house is a "sometime thing" for everybody... I try for every 2 weeks but doesn't always happen, 0.5 g per liter (1/2 teaspoon per gallon)
approximately. I don't do it surgically... I load up a power sprayer with the "soup" and give everything a bath. Done. Maybe less than ideal, but they grow and bloom so I'm not complaining.
I measure my dosages with one eye while the other one rests.
Now seriously, I know the capacity of the containers that I use to make the solution so basically I work with proportions. I don't really know, for example, hw hard is my tap water.