Spider plant question.

Spider plant question.

My spider plant has been doing better than any other plant I have, I think. But in the past week or so, I noticed that it was getting a lot more dry, brown leaf tips (I know that this is usually from using tap water - I use filtered water that has been sitting in the watering can until it is room temperature), and also that several leaves had gotten yellow and dead looking. When I pulled these leaves off, I noticed that the base of the leaves were dark and soft. I'm wondering if it sounds like I'm overwatering even though I only water when the soil seems dry? I do water the plant at least once a week, and sometimes it feels kind of dry more often. I mist it lightly, occasionally. Not sure if I'm imagining it or not, but the babies seemed to have lightened in color, and maybe become a little less green, a little more yellow. It's not directly in front of window, but across from one by about ten feet. It gets a good amount of less than totally direct sunlight just about every afternoon. Any thoughts? It's a beautiful plant, I don't want to lose it.
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