On 6/14/2011 8:24 AM, willshak wrote:

I have a Nature 2 sanitizer installed after the filter for my inground
pool. Been using it for the last 6 or more years.
I use fewer tabs per season now than before I had it. The cartridge is
advertised as being good for 6 months, but since I am in the NE US, our
Summers are barely 3 months, so I use it for 2 seasons before replacing.
http://www.nature2.com/poolproducts/...fessionalg.asp

I had one of those once, but I never saw a difference in chlorine use.