So do you think I'm taking the wrong path by going towards 2.0 cuft?
I know we have 4.5 bath but it will never be used all at once.
Probably the ideal is 1.5" distributor tube but again, many require 120K grain capacity to make this work (that's pretty much what I see as the minimum grain capacity in the market with one unit selling at 90K capacity).
I've also noticed that the 64K units comes in two different tank sizes 12x48 and 12x52. I'm sure the SFR is driven by resin volume but I also noticed that the SFR is quoted differently between these two tank sizes (I'm not sure why) unless SFR fluctuates really do change based on the tank size and type of resin used (mine is quoting 18.4 gpm with 1.05" distributor tube which means 32mm distributor tube should have higher SFR or maybe this is max rate and not constant). One I was planning to order is 12x52 tank size.
I've also received several feedback from different sellers and forum members like yourselves and majority were recommending sizes between 48K to 64K based on the stats noted above. However, I also know some sellers just use simple math by just factoring usage and not considering other factors like SFR and those considered such factors are recommending 64K (or someone has put it, correct sizing terminology is 2.0 cu ft since 64K can be achieved by adjusting the salt dosage using different resin volume).
I've read this article which gave pretty good insight on sizing: http://www.wcponline.com/pdf/0304%20...20Softners.pdf
I've also found this calculator to be most useful: http://www.apswater.com/Water_Softener_Calculator.asp
Hence based on all of these factors, it's pointing to 2.0 cuft (64K) sizing based on my very novice research.
I've also received some push back when I inquired about 2.5 cuft (80K) as they mentioned it's too large, not good for resin if regeneration cycle is too long (contrary to dittohead's pesonal experience), etc.
Trying to sift through all of these information (some probably not correct) has been a challenge, and I can see why many choose to go local dealer (like Kinetico) to get this done.
Again, I appreciate you, Tom, and dittohead's help and value all of your opinions (even though those opinions may be slightly different from each other).
I would then take those opinions and make my own decision and live with it...literally.