Cloudy/Murky tank water... help please!

So, I have a 40 gallon breeder tank (36"w x 18"d x 16"h). My parameters are 0 ammonia, 0 nitrites, and very little nitrates (I believe in the .2 or less ppm). I have tested it once a week and has been stable (no spikes, etc.) I have done two complete water changes, because my tank was cloudy. After my second water change, it was nice and clear for about two weeks or so. Now, it has this yellow tint. Not so green, and not real white either. It's not terribly cloudy, as I can see the background through the water and what not. Its just that it is noticeably murky. It hasn't got any worse and doesn't seem to be affecting the health of my lotls or goldfish. The parameters are still the same. ( I have one medium sized goldfish. He was purchased to help cycle the tank, but as it was already pretty much cycled, he just lives in there now lol. My lotls are juvies and are too small to consider him for food.) I have three axolotls, ranging from 4.75" to 6.25" (rough estimate) and the one goldfish. I have sand substrate that has been thoroughly rinsed about three times, and Malaysian drift wood that has been boiled twice and soaked maybe about four times for long periods of time. I do not feed my axolotls in the tank yet, but they do occasionally poop in there. Emilio, my goldfish, tends to eat the poop (I know that's gross but whatever) and I siphon out whatever he leaves behind. I feed him granules a couple of times a day, but I watch him eat every single pellet. I also siphon his poop that has sunk to the bottom every other day or so.

So, my main question is, how can can I fix this cloudy water? I really don't want to use any chemicals. I have been considering some plants, but I don't have any lights set up yet for them. Also, my tank receives very little sunlight. Nothing direct. It's in my living room and only receives "ambient' light.

Thank you so much for reading and I look forward to receiving any tips or advice!

It could be the drift wood leaking tannins. You could try taking it out, changing the water and see if the water gets murky again or not. Have you checked it's not your tap water that's already murky?
Don't use any chemicals. Those are usually made for fish tanks and can be toxic to axolotls.

Also I'd suggest seriously considering if it's good to keep the goldfish with the axolotls (for both the axies and the fish).

What kind of test kit are you using if your nitrates are at 0.2? I've never seen a nitrate test kit that has such low scale. Plus with 4 animals I'd expect it to go higher.

So your tank water isn't necessarily cloudy as much as it just has a yellow tint to it? If so, it could be the drift wood. Unfortunately it can take some time before it won't discolor the water.

I would also strongly suggest removing the goldfish from the aquarium.

I meant to put 20 ppm nitrates. Silly me. My axolotls aren't in there permanently yet. They pay no attention to each other when they are together (axolotls don't snap at or pursue the fish, and the goldfish doesn't try to eat their gills or anything) as the axolotls are always on the bottom and Emilio is always swimming around the upper half of the tank. I'm keeping him until I can find him a good pond home. I don't have room in my apartment for a twenty gallon at the moment. I know if I take him back, he will be Oscar or turtle food. I would feel bad. I did quarantine him for a couple of weeks before introducing him to the lotls.

Anyway. I thought it may be the driftwood. I guess I haven't soaked it enough. I just thought after four soaks and a couple of boils that it would be fine. They're small pieces. I was planning on getting a nice large piece, but now it seems like it will be a pain. Goodness.

Oh, and to all the people 'freaking out' about Emilio, he has been rehomed. I rehomed him a few days after this post. He lives in a pond now with other goldfish friends. and my water has cleared up. Thanks everyone for the input!