What's actually in those trendy activated charcoal water filters?

the main thing is that activated charcoal works through something called adsorption - it traps molecules on its surface, so it can pull out chlorine, some pesticides, and stuff that makes water taste or smell bad, but it's not actually removing dissolved minerals or bacteria. most of these filters also have other layers like sediment filters and sometimes ion exchange resins that handle different contaminants, so the charcoal alone isn't doing all the heavy lifting. the catch is that activated charcoal filters need regular replacement (usually every few months) or they get saturated and stop working, and they're not that great at filtering out heavy metals or viruses despite what marketing likes to claim.