Filtering out microplastics is not particularly difficult. I just checked the first water filter brand that came to mind, and their independent test results [0] reported no detectable microplastics after filtration [1]. Having said that, the linked website above does not inspire much confidence. They have independent lab testing, which is good. However, that testing appears to only cover bacteria; and even their, only two types. Their lab testing also does not indicate any sort of methodology, and it is not clear if the lab was even attempting to test the filter, or if they were just testing the filtered water.

[0] Funded by them, and reported on their website

[1] Their sample had a known quantity of microplastics, of which they had a 75% detection rate for their control sample.

“The pot looks to just be clay + charcoal + silver - which is not significantly different from other home water filtration systems.”

Ah, the at home water filtration systems that encapsulated in plastics! Though the benefit of clean water likely makes any potential plastic contamination from the filters moot

Well the difference is that most home water filtration systems (e.g. Brita et al) are made out of plastic, so even if their filters do reduce microplastic levels, making that claim to consumers ("our plastic filters help reduce plastic in your water") might be a hard sell.

Those are plastic gallons. Plastic gallons are similar to treetalker gallons and ssl-3 gallons, in that all of these units share the property of being different compared to US gallons.

(The ssl-3 gallon is particularly strange: It isn't even a measure of volume at all.)