Cloudy Water- All water levels okay. What's causing it?

About 2 weeks ago, my tank started getting really cloudy. I noticed a plant I had in it was decaying a bit, so removed the plant and replaced the water polishing pads in my filter and after ~2 days the water was crystal clear again.

However, now the cloudy water is back. It is so cloudy that I can barely see my axie. I've tested the PH, Ammonia, nitrite, and nitrate and all levels are fine. I just cleaned the filter last week, and do pretty regular water changes using bottled water (dechlorinated). There's no substrate (slate bottom), and minuscule specks of waste. It's a 20 gallon tank with one axie, with plastic plants and a few plastic hides. I'm using Matrix as my biomedia. Temp is consistently below 70 F.

So... why the cloudiness? Is it anything I should be concerned about, or any suggestions to get rid of it?

Thanks!

Discarding a filter pad probably isn't the best thing to do as you more than likely lost a sizeable amount of the bacteria colony.

Have you tested the water parameters? That will always be your first port of call.

I have tested all parameters. PH, Nitrite, Ammonia, and Nitrate all look great.

Although I replaced the one filter pad, I left the other 3 sponges and biomedia in place.

I've moved my axie out of the tank, but am considering putting him back in because it seems like despite the clouds there's no immediate danger in the tank?

If it's a bacteria bloom, should I just wait it out? Do you think plants might help?

Thanks!

Does seem a bit odd that the water is cloudy if you're saying that the water parameters are fine. A couple of seemingly obvious questions:

1) Did the tank go through the full nitrogen cycle? Even if it did, there have been instances of a second cycle (whatever the actual terminology is) and you could be on the money with a possible bacteria bloom.

2) Is the tank near a window or exposed sunlight/artificial light?

I don't have much experience with plants as I find them cumbersome. If I were in your shoes though, I wouldn't introduce anything new to the tank until you've isolated the issue of the cloudy tank water. Adding plants would only serve as another variable that you'd have factor into your current problem.