I have a 2016 Era. The filter is a 3M Aqua Pure, # C CS FF. My cheapest source has been Wal Mart, online. Believe about $40-45. Lowes hardware carries them but believe rhey were a bit more expensive and sometimes out of stock.
When I winterized, with pink stuff, I remove the filter if it has a lot of useful life remaining, insert the plug and pump in the antifreeze. In the spring, flush out pink stuff and remove plug and reinsert the filter which I have allowed to dry during the winter. My chlorinated city water will wash out any "bad" stuff.