Auto-Chlorination? Here might be an option.

[keithw]

A friend of mine has one of these.....

http://www.americanhydro.com/products/siphoning_feeders.asp

Designed to feed a rust reducing chemical into a well water system. Does a regulated 1gal per hour. Hooking one up to a timer should allow you set dump a set amount per day.

[aylad]

That's interesting....my question would be it if will hold up to the gas buildup (I'm assuming you're planning to feed bleach).

Janet

[JohnT]

Might work, but two issues would be of concern: Bleach is corrosive, so anything in contact would have to be very resistant to lye. Second, bleach degrades with sunlight and heat, so storage would have to be in a cool shaded area or you would have to add bleach to the tank daily, defeating the benefit of the system.

Might be better to fill the tank with a bleach water mix so the degradation would be slower (as I understand from posts here), and it could be mixed at such a concentration that it could run all day to add the correct amount of chlorine.