The leaves on my peace lily are turning brown and yellow, the tips as well as the edges?

I got a peace lily plant from ikea a 5 months ago and ever since then the tips of the leaves are turning brown, or some of the leaves will turn yellow and then go brown form the outside in. I water it with 800 ml of water every 2 weeks and the plant is next to a window on the floor getting diffused sunlight everyday. In Australia it is currently, on average, Around 15 degrees Celsius (59 degrees Fahrenheit),I’m not sure if that has something to do with it. Do I cut of the brown tips or dead parts of the leaves? I don’t know what I’m doing please help.