The Triple Big Blue I had purchased: https://www.amazon.com/gp/product/B00MTTHYBI/
NOTE: as with a lot of amazon products, you have to watch for the deals... Currently at $300+ which is more than I paid--also, there are several suppliers of these canisters. Lastly, I purposefully purchased the 1" input/output to match my existing water lines.
Poly-Salt Filter: https://www.filterwaterdirect.com/catalog/salt-free-water-treatment
NOTE: Looks like he has the next generation housings available--the style I had purchased looks to be no longer available.