Hydration (with dromlite + aqua mira)

Unless your water bottles are the collapsible type and space is tight… otherwise, I would treat the water in their own bottles (and filling up the 4L bladder to the level needed).

so what you're saying is just fill everything up and treat it all simultaneously?
or treat the plastic bottles only, fill up the 4L with untreated and just treat it as I put it in the plastic bottle(s)?

I was assuming that on the trail — you drink from the water bottles first — and then replenish from the 4L bladder when needed? It so, it doesn't hurt to treat all the water simultaneously. After all, if the water is cold, it can take up to 4 hours to properly treat against protozoa cysts (giardia, crypto, etc.)! Longer treatment time never hurts.

OTOH, say you are nearing camp… you fill your two water bottles for drinking and you fill the 4L bladder for cooking and washing. In this case, it may be wasteful to treat the 4L bladder. Perhaps better to leave the 4L bladder untreated — use the water for cooking and washing — and whatever you have left — treat only if you plan to drink later or the next day.

As for filtering out particulates, take a look at my light and compact water scoop with built-in filter.

If what you are doing is filling up a big sack, treating the water in it, then pouring it into smaller bottles, the big sack is actually useless weight. Just fill up the smaller bottles directly.

To make that easier, save the Aquamira mixing caps when you get a new set so that you have extras. Or else use the caps the smaller bottles have. Mix up your Aquamira in individual doses for each bottle.

Being someone used to hiking in Southern California I still made the newbie mistake on the PCT of carrying way too much water. I would carry 5.5 liters from each source and top it off whenever I could because I was afraid to let it get empty. I really only needed 3 liters. (Some people actually need more than 5.5 so don't go by my numbers.)

What I learned that made the difference was to drink my fill and then some at the water source. At least a whole liter in my belly. Drink mix (I liked Crystal Light Hydration) helped get it down.

Cooking at the water source helps, too. Either eat at the water source or I found that a cooked meal, as long as it wasn't soup, could be packed in my pack carefully to be eaten up to 2 hours later. Wrap it in a pot cozy and put in a ziplock bag.

If you are going to use your Dromlite, MSR makes a coffee filter thing called the Mugmate (REI sells them for $17, ouch). It exactly fits into the large Dromlite opening, strains out all the floaties, and it weighs < 1 oz.

4 liter blatter plus a couple (2) 1 liter bottles is a lot of water weight. Plus those MSR blatters are not exactly light. How far appart are your water sources? I'd rather carry a pump then lug 6 liters of water around.

Carrying 4 liters of water while waiting for the treatment time negates the weight savings of chemial treatment.

Where I hike there is water about every 1-4 miles. So I usually carry a pump and fill (top-off) a 1 liter bottle every water hole. Ya the pump weighs a pound but a quart of water weighs about 2 pounds.

I believe he is going to the So Cal portion of the PCT where water is frequently 20+ miles apart.