Just get a floating tablet dispensor and skip the expensive cartridge altogether. What I like best about a floater is when the kids are active in the pool the floater bobs about and dispenses more chlorine as there is more turbulance. This is like a cheap form of automation. Do watch your stabilizer levels as the summer progresses you may have to switch to another form of chlorine that is free of stabilizers (bleach, calcium hypochlorite).