It was kept outside in summer with partial shade and moved back indoor (~72F) in Sept when temperature started to come down. Indoor, it is kept in a plastic storage box (with some holes for ventilation) with 12/12h light from a 100W fluorescent bulb (1.5-2 ft above indirect). The brown/yellow leaves come a while after move in.
I will try reducing light. Hope it becomes better.
kulamauiman, for salt accumulation problem, do you recommend to change the medium immediately? or rinse the medium thoroughly with rainwater/RO water?