i've been learning how to do it old-school way

in actual fact, the two things that make water drinkable are:

1. fine filtration, but literally denim jeans are sufficient

2. active carbon - easiest is to just use freshly made charcoal from a fire, helps to crush it up but not essential

second thing i would mention is that you can achieve extremely fine filtration with common kitchen towel or unscented toilet paper, the TP is the absolute best but the kitchen towel is pretty good, it is enough to stop the carbon dust from grinding up your charcoal

if you then take your water, and throw that carbon in, idk how much is best, i suppose if the water is mostly clear, probably about a teaspoon of fine powder per litre, more carbon fol less fine and more water

mix it up nice, and then run it through a funnel with your TP filter and done

it is slow, but it comes out clear and tastes like you got it by opening your mouth and sticking out your tongue as it fell from the sky