Hello, been lurking here and soaking up information on softeners.

I've found what appears to be a great local company to install both a softener and an RO. Standardized parts, pricing, warranty, service, longevity, and answers to all my questions match up to what I've read here and elsewhere about this industry and selecting a system.

That is, except for their sizing recommendation, which seems off to me. That said, I am hardly an expert so I'd like to get a 2nd opinion from this forum.

House is 2.5 bathrooms, with an additional bathroom and wetbar sink to be added in the lower level within the next year for a total of 3.5 bathrooms that I am planning for.

Household is 2 adults, 1 toddler, and 1 on the way. House is on city water and water usage per month (in the winter to try and eliminate landscaping and pool watering costs) is about 5-7k gallons. For the 3 current people that breaks out to 66 gallons per person per day on average (6k/3/30day). I might still be counting some landscaping water in there though.

Water company report says hardness is between 7 and 20. Softener company says that their experience leads them to plan for 25-30 for this area to avoid service calls.

Company is recommending their "48k size", which they say translates to 1.5 cu ft of resin. They claim regen is designed for about every 5 days with a targeted 7lb per cu ft of salt usage per regen. Of course, with a Clack WS1 it is metered on demand and they say they plan for about 1800 gallons of use between regens. Also quote a 20-22gpm flow rate. I also picked up on what was somewhat of a careless attitude when it comes to salt/water efficiency, so that makes me want to question their numbers even more.

Flow rate looks good, but I'm not sure if the rest of the numbers add up to me. My main concern is that 1.5 cu ft is too little based on what I've seen here. I think I should mostly be concerned about getting the cu ft right, and then I can tweak the Clack programming as desired. Does that sound right?

Overall I'm looking for a size that will meet my current needs without too much waste, but can grow as my family grows and I can reprogram the Clack as needed to adjust for that.

I appreciate any forum opinions. Thanks!