[Arizona_928]

I would not use water jugs for any acid storage. Lid securing, and the fact that milk jugs tend to break when dropped/sensitive to UV.

Pool acid/muraic /hcl can be bought in gallon sizes and a little thicker platic and securing lid. Understand that h2so4 is different than hcl. I would use a thicker plastic. Water jug is like a thin water bottle, I would aim for Gatorade bottle thickness (you might be able to use one. I don't use it in my lab and don't recommend). They sell individual squeeze bottles for this, or glassware storage... How much chemical are we talking about? It's kinda rare to see macro chem at a home level without catching the radar of big brother. Or at least I did when I ordered a bunch of chemical to phosphate

You can re-use electrolyte. There should be a calculation. I'll have to check my analytical chem text.