The FAQ says the basic filtration speed at 95 degrees Fahrenheit is 0.5 liters in 3.6 hours. That's about how long it takes me to drink 2 to 3 liters at Burning Man at that temperature. Of course, I'm active during the day. I guess if I'm on a liferaft at see, I won't be going anywhere. :-> Still, I'm not sure I'd be happy with a half liter every 3 to 4 hours, assuming the water is 95 degrees.

I'm unable to determine what the specs mean for the Seapack:
"Volume: 1.8 liters"
Does this mean the bag will let me put in 1.8 liters, then filters it at the rate of a half liter every 3.6 hours at 95 degrees? And it comes with 5 syrup bags that produce 2.5 liters of 'survival drink"? One bag per half liter, it seems.

I note that a serving size of the drink is 8 fl. oz. :->

Their catalog says that the syrup is required to drive the osmosis process. I'm sure this particular bottle of this particular syrup is not required, but you'd have to find the right chemistry if you wanted to do it yourself.