I agree with the sunburn diagnosis. PL's burn very easily. The light coming through mini blinds and sheers isn't enough, though. Somewhere that's not outside in the sunshine but is more brightly lit than the location it is pictured in would be good. Also agree with changing to soil to improve aeration but would personally do it with mulch instead of perlite. I don't like the looks of "white-top" soil and perlite just takes up space in the pot without offering any benefit to the plant. That soil is hard to see clearly but looks like it has a lot of peat which is hideous stuff that never seems to dry out until suddenly it's so dry it won't get wet again. Also "floats to the surface" like perlite. Read some of the other posts on here about PL's and other plants which contain root pruning advice from AL. You may decide more root pruning than you already did would be good. PL's make "pups" to increase themselves. Each individual part makes 1 leaf at a time and over time a PL can develop a whole family. Yours looks like 2 clumps where the biggest one has one growing eye and the other clump has 2 eyes. These clumps are probably still connected to each other by a root which could be severed so you could but each clump in a separtate pot, or back together in the same pot. It's been my experience that when PL's get severed from each other they usually send up new eyes and/or whole new pups.

Yellow leaves huh. . . It could be over fertilized, but these plants seem to be sensitive to so many things, it's hard to say. It is usually a watering issue. They don't like to be 'wet' but they really don't like to go dry either. Lack of water and they droop, very dry the leaves fall completely over. Too wet, the leaves turn brown and crisp. I don't think too much light would cause the leaves to turn yellow. I think I would start by checking the roots. Do this by taking the plant out of the pot, removing as much of the soil s you can. If the pot was sitting in a dish for drainage and the dish held water, it could have root rot. You will know this if the roots are soft and mushy or smelly. At this time also check for bugs. If everything checks out repot it. What size is the rootball? It is possible it is in too big of a pot which would cause root rot too. You should be able to put your fingers between the rootball and the side of the pot, any bigger is too big. Amend the soil with perlite and bark (orchid bark) 1-1-1. For now, until it starts to recover, no fertilizer. I wouldn't feed it for a couple of months. Put it in bright, no direct sunlight. The new soil is fast draining so check it often and water as needed. Stick your finger in the soil, if it is dry 2" down, it's time to water. I have a huge one (3' tall x 4" wide) I take it to the tub about every 5-7 days and pour 3/3 gallon buckets of water in it, letting it drain well each time. Then I let it set there until it is completely done draining. Mine sits in front of a west facing window, after a few hours I pull the blinds so it gets filtered light for about 4 more hours. Your plant is probably smaller and that would be too much water, but just water til the water comes out the bottom. Do this a few times, this will help flush the salt buil-up as well as the excess fertilizer it is holding. Hope this helps.

Anthuriums are epiphytic (meaning they grow up in the canopies of the rainforests on the sides of trees), just like orchids, and they grow in the same habitats as orchids as well. Tho they can adapt to growing in a fast draining soil mixture that's blended with orchid bark, perlite, and charcoal. They are closely related to Peace lilies. Peace lilies also prefer a fast draining soil mixture that doesn't stay soggy either. So as long as the roots can breathe and have access to plenty of oxygen, you'll never have to worry about "overwatering" them. Both of these plants live in the rainforests, where they can get rained on on an almost daily basis. So they're no strangers to water. It's a common misconception that overwatering a plant is about giving them too much water, when it's not. It's when the soil mix holds on to too much water, cutting off the supply of fresh air to your plants' roots, causing them to suffocate. For my plants, I don't ever let them dry out. But I also use a proper soil mix that doesn't hold on to too much water either, no matter how much I water them. With it being wintertime, I don't water them as often as I do throughout the rest of the year. I have a similar sized plastic bucket that I sit my plants in and fill it up to the soil line with water, and I let them soak for about half an hour. Then I'll remove the pots and let the excess water drain away. You notice how the runoff will have a slightly brownish tinge to it from all of the dissolved solids in it. That's when I'll flush the pot out with some fresh water, until it starts to run out clear from the bottom. This helps to get rid of any excess mineral deposits and fertilizers that would otherwise buildup in the soil over time. These plants come from the rainforest, and they absolutely love water. But they also need for their roots to breathe as well. And I don't worry about spraying them either. They'll do just fine without it. Here's a couple of links to the Exotic Rainforest's website for properly caring for these plants. It offers a wealth of accurate information on these wonderful plants: Caring for Spathiphyllum & Growing the Tropical Anthurium As for the old spathes, you can just let them naturally die back completely on their own. They don't expend energy from doing this. In fact, letting them die back on their own gives them a chance to reabsorb any nutrients and/or chlorophyll from the spathes, which they can reuse in other areas of the plants. This is why they turn yellow beforehand. Once the old spathes have completely turned brown, they'll easily separate from the plant when you go to gently pull on them. This is no different than when the leaves of deciduous trees change color before the trees shed them in Autumn. Because they're reabsorbing all of the nutrients and green chlorophyll to reuse again in the Spring, rather than having to make them from scratch all over again.

Overwatering isn't about using too much water, but rather how much water remains in the soil afterwards. You want a fast draining mix that doesn't stay soggy. So the plant's roots can still breathe. Fresh air is just as vital as fresh water. Probably even moreso. Sure their leaves take in carbon dioxide, but their roots also take in fresh oxygen as well. When they can't do this, their roots suffocate and eventually end up rotting. Think of it this way, you need both water and fresh air to survive. But go without either and see which one you die from first. Plants are no different. When you do water your plants, flush out the entire pot with lots of fresh water, and let the excess drain away.