my plant

my plant use to grow day by day but now its no longer growing that way it takes it a week to or two days to grow. what i noticed is that the water colour has now changed to green with some algae i will try and upload some pictures later on. in the morning there are always purple flowers growing but during the day they die. i inserted my plant in a small quali juice bottle which kept the roots together. i never changed the water, i only  add water once a week. what bothers me is that every time when i change my plant position some leaves fall decreasing the number of leaves. this week two leaves turned brown with a few leaves pink in colour.