I’ve used Katadyn products out hiking. They take a little work to get the water but are very effective.
The mold was probably caused by contaminants which were in the jugs before the water was added. Either that or the water wasn’t pure.
You can reduce it by sanitizing the jugs before adding water.
is it wrong that i just plan on drinking homebrew beer for my longterm solution? I do however have about a 5 year supply of Q-Tonic water stored up, doubles as an anti-malarial and reduces the effects of restless-leg syndrome.