Continued from "SWG Size."
I was ready to "make a claim" under my warrantee against my pool store/builder for installing a SWG that was too small for my size pool. But before I could explain my case, the service manager told me that 3 years ago, they had a letter in hand from Zodiac, who manufactures both the Clearwater LM2 SWGs and the Nature2 systems, that the Nature2 system installed on my pool would effectively reduce the size of SWG required, as though my pool were 10,000 gallons smaller.
This made sense to me, since my first year with the pool, I didn't seem to have problems with the chemistry and algae. The second year is when, after making a conscious decision not to replace the Nature2 cartridge (>$100) that I began to have problems. The service manager said this is often the case. I know this is only anecdotal evidence for the Nature2, but, it fits my experience.
Of course, it's a racket though. Why not just install the larger SWG for a few dollars more, and not have to pay $100+ every year for a new Nature2 cartridge? So, after politely expressing my distrust of the Nature2, I asked if the store couldn't help me out by at least giving me the larger SWG (cell only) for cost. The service manager agreed, and tomorrow I'll get the Zodiac Clearwater LM3-24 (cell only) to replace my LM2-15 for $250. Hope this might be helpful to some of you.