Direct sunlight would be outside in direct sun. The sun coming through your windows is already going to be filtered light. It would be very good for your tree to repot into a container with drainage, use something like the 5:1:1 mix and place it right up in front of a southern facing window where it recieves as much light as possible. I grow quite a few ficus benjaminas. They have the same general needs as your tree. Naturally, these trees want as much light as possible. Anything that says they don't like direct light is false. It's just that indoor grown leaves can't handle full outdoor sun unless acclimated. In the winter months, I keep the tree in front of a southern facing window with the addition of grow lights. I have five 55w (250w equivalent) 5500k grow lights above the tree. In the summer, I acclimate the tree over a span on a couple weeks and then place it in full direct sun all summer. That is when it puts out the most growth. Literally grows a couple feet every summer. the tree is 7 feet all and was under 4 feet tall when I got it a year and a half ago. Currently in an 18" terra cotta pot in Al's 5:1:1 mix.

Use a dowel/unfinished chopstick/skewer. The first time I checked moisture with a dowel I found that the moisture meter I relied on said the soil was bone dry when it was still very moist, and my ficuses definitely love drying out between watering. My 3/8" dowel, broken in half with all four ends sharpened in a pencil sharpener, is cheap, fast (it only has to be in the soil for a few seconds), easy, and completely reliable. BTW, I'd get rid of the moss or whatever is covering the soil because it slows evaporation and provides a great habitat for bugs. Definitely don't water until you're positive the soil at the bottom is completely dry. At that point there's still a significant amount of moisture inside the particles and available to the roots, so don't be nervous; just check the soil moisture daily once the top of the pot starts to dry out, and keep your watering jug locked away until the dowel comes out completely dry and unstained by soil.

I agree the damage is almost certainly from pool chemicals. If you haven't flushed the soil VERY thoroughly, please do. Make sure that a volume of room temp water equal to at least 10x the volume of the pot the plant is in makes its way slowly through the soil. If you're worried that represents over-watering, you need to take a critical look at your soil choice, but that's another conversation. If you're using a cache pot or a saucer under the plant, make certain the bottom of the pot is lifted well above any water that collects in the saucer/cache pot so there is no pathway for the effluent to make its way back into the soil after it exits the drain. Then, as Jean mentioned, it becomes a wait and see kind of deal. Withhold fertilizer unless/until you see new growth. Water when the soil is almost but not quite dry near the pot's bottom. Use a wooden skewer or, preferably, a 1/4 or 5/16" dowel rod sharpened in a pencil sharpener. Push it to the bottom of the pot and water only when the tip shoes nearly dry when you remove it. The background info provided forces us to believe it's from the unscheduled swim it took, but I still must ask if you have an ion exchange water softening system - one that requires the addition of salt from time to time? On the chance the answer is 'yes', priority one is figuring out a work-around for that. Al

I would repot your Fiddle Leaf Fig with new good quality potting soil and into a slightly bigger pot with drainage holes. A clay type pot is better than plastic. Make sure your Fig isn’t being exposed to hot air from a vent and turn the plant every now and then so that it gets even light