The Duoclear contains a Nature2 mineral unit so they also recommend a FC level of .5 ppm in the US!
I would not recommend using the mineral cartridge. However, the Duoclear units are undersized as far as SWGs go because they were desinged to be used at much lower than normal FC levels (that do not work in the long run!)
alternative-sanitizers-and-chemical-free-pools-the-truth-t3025.html
According to the US Duoclear website and manual:
FC is .5 - 1 ppm and CYA 40 -80 ppm
http://www.clearwater-usa.com/pdf/DCIns ... Manual.pdf
All the other Zodiac SWGs have a recommended CYA level of 40-100 ppm and a recommended (and too low) range of 1 -3 ppm for CYA (I used to sell all these units and do know a bit about them).
I know that the Nature 2 spa units can only be marketed as an algaecide and not as a sanitizer in Canada so I guess they are a bit stricter than the EPA in the US. Funny thing is that the Spa system actually can sanitize better because of the higher water temps when used with MPS.
The Canadian manual for the DuoClear reommends CYA of 30-100 ppm btw and a FC of .6 ppm when using the mineral cart and 1-3 ppm otherwise so it's bascially the same as the US instrcutions.
http://www.zpc.ca/e/manual/DuoClear130_ENG.pdf
Bottom line is this:
Since these units were designed for low FC levels they are grossly undersized in terms of actual chlorine production so if you have one that the upper end of it's range is the size of your pool you might have a problem maintaining enough chlorine. If you have overized the unit you should be OK.
The water balance you want to use is:
water-balance-tips-for-a-swg-t3663.html
If you have an usesized unit I would recommend running the CYA at 100 ppm and keeping the FC at 5-6 ppm.
DO NOT USE THE MINERAL CARTRIDGE!
