I recently brought home a few new plants- a calathea lancifolia, an alocasia, a small dracaena, a silver pothos. All of these plants are in my connected kitchen + dining room/bay window. I have a very old nerve plant that's been dying and suffering ever since we moved to this new house. I thought it was because of the move or inconsistent watering, so I had kept it alone on a shelf and have been giving it plenty of water, but it never seemed to recover. When it grows new leaves they stay for a while, but then they turn yellow and drop. It basically has long empty stems with a few little leaves at the ends.

To the bug issue- I first noticed them in the alocasia. After I watered, I looked at the soil in the sunlight and noticed tiny, tiny silvery bugs, they are skinny and move quickly around the soil. They are not on the leaves or stems at all. They start moving when I blow on the soil or after I water. They most closely resemble thrips or springtails from what I've seen online, but I'm not sure if its an exact match. They are so extremely small (a millimeter or less) that I never would have noticed them except for the sunlight on the soil made them stand out as they quickly crawled around in the wet soil. The alocasia doesn't seem sick as far as I can see. Then I began inspecting my other plants in the room. I noticed a few of the same bugs but less in the calathea lancifolia. None in the dracaena so far but if I stare at it long enough one might show itself. I saw a fair amount of them in my 3 year old african violets soil. A fair amount in the silver pothos- which also had some gnats from the greenhouse on it when I first bought it but they haven't shown up since. The pothos and african violet I also noticed an extremely tiny dark reddish brown "spider"- it reminds me of those tiny bright red ones you see outdoors, but it was darker in color and just crawling in the soil. I believe its some kind of soil mite. Again nothing on the leaves or stems of any of these plants.

Then I got to the old sick nerve plant, and noticed many of these tiny silvery looking bugs quickly crawling in the soil after I watered. I threw the nerve plant out in my garbage in the garage now. I'm not sure if it was the source of these bugs but it seemed to have them the worst. The next worst one is the alocasia or the african violet.

What I've tried so far is a mix of water and Dr. bronner's castille soap (1 tbs per quart) and I sprayed it just on the soil. That was last night, and this morning I noticed bugs still but maybe fewer. Whenever I see one I've been directly spraying it with the soap water. I can't really tell if its dying instantly since they're so small. I've been getting very paranoid/obsessive on it today and I keep going back and staring into the pots for several minutes until I see one of the bugs then I spray it...While I was doing this I found a tiny little worm in the calathea lancifolia- it squirmed like an earthworm but it was only a couple millimeters in length at most. Very pale yellow almost white but translucent. I believe it was a fungus gnat larvae because the google images look just like it. I dug a bit and didn't find any more of these worms.

Sorry this is getting extremely long. A summary- found three types of bugs in the soil of these houseplants- tiny silvery looking ones that quickly crawl in the soil, some very tiny dark red brown spiders in the soil (soil mite?), and one pale yellow/white translucent worm (fungus gnat larvae?).

Any advice on how I should get rid of these bugs in the soil before they harm my plants would be greatly appreciated!! So far the plants seem okay but don't look perfectly happy if you know what I mean. I feel that things could get worse. No damage to the leaves or stems as far as I can see.