replacement softener sizing
First, thanks in advance, this is a great forum!
I've been reading in this forum and elsewhere, and I think I have it figured out, but just wanted to double check...
The city claims my hardness is 17 grains and "less than one part per million of iron". They also claim to add 4 ppm chlorine.
By calculations I've read here, for my 2 bathroom modest house with 4 people, I use about 4 * 60 = 240 gallons a day.
I know there is iron in the water, some times it comes out of the tap yellow. (the cold water isn't softened, something I'll need to correct), so I'll assume 1 ppm of iron, which would add 2 grains.
So, each day I need to remove 240 * 19 = 4560 grains.
I've gathered that I want to regenerate about once a week, so I need to remove between regenerations 7 * 4560 = 31920 (round up to 32,000) grains.
From http://www.purewateroccasional.net/hwmeteredsoftener.html I found a chart that I interpret to mean I have these options (I've rounded):
size cu ft 6# 10# 15#
9x48 1.0 20k 25k 30k
10x44 1.25 25k 31k 37k
10x54 1.5 30k 37k 45k
And since I want to use as little salt as possible, I should get a unit that is 1.5 cu ft.
Have I gone wrong somewhere? I want to install it myself to replace the 18 year-old Culligan that came with the house when I bought it. That one is 8x44 (.75 cu ft). We've been in the house about a year, but, the thing never regenerates automatically anymore (I think the flow meter is busted), so I can't say if it ever worked right.
Help me Obi-Wan Kenobi, You're My Only Hope!