Here is my implementation using the Intex Above Ground salt water generator (Model ECO 8110 28669EG ) for an in ground pool. I just finished this past week. I bought the the SWG in May 2015 from walmart for $100 a piece. this month I took the time to put everything together. The basic philosophy is to keep the INTEX unmodified in case I have to get warranty service. I have two units in series because of simpler plumbing layout (even though parallel would be better). Right now (summer) It gets hot and rainy in florida so two units will be running,then I intend to run one unit the rest of year. The intex plugs into a weather resistance GFCI outlet which wired to timer switched output. Another words the intex swg powers on whenever the pool pump turns on. I have picture of this but I have exceeded upload quota.
If one unit breaks, then I can always order a replacement ($120 to $150) from Amazon (2 day shipping). The broken unit will be either in transit for warranty service or if out of warranty becomes spare parts to fix the other unit. I used FLexible SPA PVC to hook up the unit. I can easily bend the pipes using heat gun/hair dryer should Intex drastically change their input/output water ports in future revisions.
There are few key posts from troublefreepool that got my ideas from. They are worth reading
Also I had to unglue my existing PVC. The previous owner poured concrete around pool plumbing so I had to be extra cautious.
One project I need to do is replace the intex hose that connects the two Intex unit in series with Flexible PVC. The other is to replace the makeshift concrete block shelf to hold the intex units with something "better"