Ti plant issues

Hello there... you all were so helpful to me when I was dealing with my gardenia, I wanted to know if you had any suggestions for my Ti plant.

I purchased my Ti plant back in February at a nursery that I work for. I kept it indoors until it got warm enough outside. Through the late winter and early spring, I had it in a west window with a humidifier next to it. It began to get brown tips on the leaves. I eventually found out that you aren't supposed to water it from the tap, since it may have too much fluoride. I began using my aquarium water instead, and figured it would stop browning.

I placed the plant outside maybe a month and a half ago, gradually letting it receive more sun. Now, it gets 4 or more hours of direct sun, but shade other times during the day. I live outside Washington DC, and we have very high humidity here in the summer. I'm still dealing with brown tips, and it seems to have gotten worse. Now there are brown spots on the leaves too, not just the tips. The spots are crispy and light tan, not dark. New leaves are also dealing with it too.

What am I doing wrong? Too much light? Any suggestions would be much appreciated!

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