This took forever to get right, but all my filament dryboxes are at 10% and I can’t get it any lower.

Nice! :) Mind to share the parts you‘ve used and post a bit more info? :)

those all look like snapdryers.

I am using PolyDryer Box from Polymaker, and the colored sackers are https://www.printables.com/model/865327-airlock-dock-stacker-for-polydryer

Other than that, nothing much other than an assortment of PETG.

What's your ambient humidity? It's usually around 80% here and I can barely get my dryboxes down to 30%

Same for me

I think 40-50% we just got off winter

Bruh, that's getting on the dry side. You probably should print one of these:

https://www.printables.com/model/1657964-prusa-pro-acu-design-files

That's really good. Much better than the ones I have.

What boxes are they? Cereal?

I find mine start off at 10c but creep up easily. I've only just started with mine. How often do you cook out the beads?

Does it make a difference? The extruder doesn't evaporate all wetness?

for some filament, at least PLA and PETG, you don't want to filament entering the extruder to be too warm because it can soften and cause jams / under-extrusion

If there's moisture in the filament it vaporises in the extruder, causing steam bubbles that expand and disrupt the laying down of plastic, usually causing inconsistent extrusion lines (which itself causes poor layer adhesion). Some of the filament may end up being heated in the extruder slightly longer than other bits depending on these steam bubbles, which can cause overheating issues like stringing and oozing, etc..

Not to mention that filament that has absorbed water tends to become more brittle, which can lead to the filament snapping off before reaching the extruder. As a result, a filament's shelf-life is usually dictated by how quickly it absorbs moisture (and also whether UV from the sun weakens it at all, but that's a lot easier to manage).

They are Polydry boxes. And I don't dry by beads often enough. Though we haven't hit summer yet here. So I can't say how well they seal. Should be good though since my oldest box kept 15% all winter.

Brittleness didn't get talked about enough. I couldn't figure out why my fundament was breaking on retraction to my Creality Hi CFS over and over again. It was driving me nuts. The prints all came out looking great, so I thought I wasn't having humidity issues and that there was a mechanical problem somewhere. Took the whole damn thing apart to clean and check that everything was tightened to correctly. Multiple times.

I just needed a filament dryer.

I had no idea that filament snapping on retraction could be caused by wet filament, and I read about 3D printing a lot more than most. Almost all threads about wet filament are about print quality, and people rarely mention brittleness. Conversely, in threads about filament jams/errors, most comments focus on the mechanical parts (tension, loose screws, debris in the gears, temps, etc.) and rarely mention wet, brittle filament as a possible cause.

If you're reading this and don't have one (or another method for it), get a filament dryer. I recommend the Creality one when it goes on sale as it's one of the cheapest options that can hit the high temps needed for some filaments and that can also be used as a dry box you can print from. My only gripe is needing to prop the lid open when it's drying to release the humidity. It's silly that it can't dry filament properly without the door cracked open.

I have like 28% and I am printing PCTG and PETG from it exclusively xD