I have recently completed some emergency disaster training. As we try to help individuals become more self sufficient after a disaster of any kind the water supply is the # 1 priority to keeping people on their feet. As I wash washing clothes today I thought how great it would be to have a small plastic vial of clorox to put in out emergency kits. About 3" tall and 3/4 to an inch in diameter. If the container also had a pointed tips like eye drop containers, counting the drops would be simple. Since there is alreay a supplier for eye drops in that size you wouln't have to reinvent the wheel. Post the formula on the label, as to how many drops per gallon for purifying water. This would be so easy and could be used for the car kits, home and camping. With the push on for preparedness I think you would sell millions. Affordable is important as many companies jack up the price of common things because it is intended for emergencies. Those who are prepared and have simple methods to accompish the basics will fair better and be able to help more people.
I beleive this would be cost effective and simplify the process for many people.