No idea on a Polydryer mod. I’m not familiar with those. But for how much it helps, there’s a long thread about it with some other stuff. https://forum.bambulab.com/t/filament-drying-preliminary-results
It helps a lot. I was also having moisture issues this past summer and that’s what led to my involvement in this. I’ll put some before/after photos.
It still takes a while and there’s diminishing returns like anything. Even though you can dry to arbitrarily low moisture content, going really low still takes time. It’s because at lower humidity in the filament dryer the slow step becomes water finding its way out of the filament.
There’s another user here who built their own dry air supply and they related that they weren’t able to get below 28% RH in their Sunlu filament dryer. With a dry air purge they hit 16% RH in their dryer in 11 hours if I am remembering correctly.
Here’s PETG HF used for some netting clips. I printed straight from the shipping bag and got doughy surfaces and some lifting from the build plate. After drying the clips were perfect:
Here’s PLA before and after drying:
Not everyone needs dry air for filament drying. A lot depends on your humidity and even how and what you print. But if you are having moisture issues and regular dryers aren’t fixing it, dry air might be the sauce it takes to fix things.