My 1994 Culligan N8 softener has died. I would like a recommendation for a DIY replacement.
3 bedroom, 3 bath home. 1 hr north of New York City.
Washer, dishwasher. No hot tub or other high usage fixtures.
2 adults. In addition, 2 adults and 3 grandkids for a few days at holidays.
Private well, 140 feet. No odor. No color. No sediment.
3/4 inch copper line from well tank to old Culligan softener.
3/4 inch copper line from old softener to house.
Culligan bypass valve (part of softener).
Well tank and old softener in basement, 4 feet apart.
Pressure gauge on line just after well tank: 40 psi min, 60 psi max.
Bucket test -- at upstairs bathtub, both faucets wide open: 40 seconds to fill 5 gallon bucket (7.5 gal/min).
Bucket test -- at "bib" between well tank and old softener: 25 seconds to fill 5 gallon bucket (12 gal/min).
Typical usage: one shower or dishwasher or washing machine at a time. Occasional usage: two fixtures at a time.

Water test by local independent lab, 02/2011:
MF T. Coliform: absent
Lead (IMS): 8.5 ppb
Nitrate: 1.20 MG/L
Nitrite: Iron: Manganese: Sodium: 7.84 MG/L
pH: 7.5
Hardness, total: 308 MG/L
Alkalinity: 158 MG/L
Arsenic: Turbidity: 0.8 NTU
E Coli: absent

The existing salt tank is 40 inches high, and 18 inches in diameter. I would like to re-use it, if possible.

I have read quite of few posts on the forum, and checked the online calculators from Ohio, Quality, and ASP. I feel I have a basic understanding of what I need, and hope the information above is complete.

Thank you in advance for any specific recommendations you can provide.

Regards,
Bill Wheelan