Lucky Bamboo Plant

I've had my braided ponytail lucky bamboo plant in my office for about 3 weeks now and it seems the tips of the leaves are browning or becoming dried up. I water it once a week with distilled water and every other week i water it with plant food distilled water mixture.

Does the plant look normal or could the drying up of the tips be from the fertilizer or room temp? The building keeps the heat on and yesterday the temp outside was 73 and in my office was 81. Other days its around 70.

Here are some pictures.

also, when i water once a week i let the water get to the gravel level.

Would i need to mist water on the leaves every so often?