Just had me thinking about this. I am at 3 cups a day right now. So 5 gallons in 23 days.I have had the lift pump version on my 20L for 6months or so. My worry would be how much evaporation you’re going to have over 23dasy….. I go through 5 gallons or so a week of rodi in my 20. Do you have a storage tank that will hold 20 gallons of rodi while you’re gone for 23 days. The filter will float sometime so I attached a shell to the end of it and now it sinks to the bottom.