Here is the data:

single story house
2100 sq. ft.
4 people
2 full baths
lots of laundry
city water

free chlorine 4
total chlorine 4
pH 8.2
Alkalinity 345
Copper 0
Iron 0
TDS 600 (without salt)

flow rate unknown

total hardness 50 ppm (pool supply store test)
total hardness 90 ppm (water company)
total hardness 160 ppm (in house drip titrate test)

We've been in the house since it was built 10 years ago. Have been seeing lots of white buildup (scale) on fixtures and glass shower doors.

What capacity softener do I need?

If you intend to purchase locally, have all of the locals come out and test your water and give you a bid - get them in writing. Ask each of them how they determine softener size. Talk to neighbors and friends to see which companies provide great service. If you intend to purchase online and DIY, call several companies to ensure they are capable of answering your questions satisfactorily.

You want:

1. High quality resin, 10% crosslinked. The chlorine levels in your water will damage resin over time. Higher crosslinking will withstand the chlorine. Low-quality resin is only 6% crosslinked, entirely unacceptable for you.
2. Gravel underbed
3. noryl bypass
4. Fleck valve/controller (unless you are interested in Kinetico, which uses an entirely different system)
5. Plumb the softener with bypass valves such that the softener may be removed entirely without disrupting water flow to your home. This is a good precautionary measure that will prevent many headaches when maintenance is necessary.

Once you have a softener, I can help with programming to ensure it runs as efficiently as possible.

Below is the unit I've chosen based on your recommendations:

Fleck 5600SXT Electronic 3/4 Inch Meter On Demand Control Valve Water Softener 32000 Grain Capacity.

9x48 resin tank
1.0 cubic feet of resin
9 gpm service flow rate
2 gpm backwash flow rate

Selected options:

Fleck Valve Connection: 3/4 Inch Noryl Yoke with Noryl Bypass Valve
Tank Color Option: Almond
Brine Tank Size: 18x33 Round Brine Tank
Res-Up Feeder: No Res-Up Feeder
Softening Resin (1.0 cuft): NSF Approved High Capacity Cation 10% Crosslink Softening Resin (Imported)
CanPro MediaGuard: No CanPro

This does not appear to have a "gravel underbed" - is that critical? Ohio Pure Water includes a "salt grid", however. I'm guessing they don't serve the same purpose, right?

The gravel underbed is installed in the resin tank and, yes, it is critical. It causes the water to flow evenly to prevent channeling and provides more effective backwashing. Softener companies tend to downplay the importance of the gravel underbed because gravel is heavy and expensive to ship.

CR10-100-BOX
Cation 10%, 1 cf box
13039

The bag inside the box shows:

Nelson CR10

CR10-100-BOX
Cation 10%, 1 cf box
13039

The bag inside the box shows:

Nelson CR10

Enter the master programming mode on the valve controller and set as follows:

1. DF - GAL
2. VT - St1b
3. CT - Fd
4. NT - 1
5. TS - U1
6. C - 22.5
7. H - 10
8. RS - FS
9. SF - 20
10. RC - 0
11. DO - 7
12. RT - 2:00 (or other time when you are unlikely to use water for a couple of hours)

13.
BD - 60
BW - 10
RR - 10
BF - Find your BLFC sticker (look at the attached pic - the sticker is inside the red circle) If it is 0.25 GPM then set BF at 8. If 0.5 GPM set at 4, if 1.0 gpm, set at 2.

14. Ensure all days are ON, unless you have a specific day of the week when you need the softener to NOT regen.
15. CD doesn't matter unless you set a day to OFF in step 14
16. FM - t0.7
17. should not be available

Once the valve is programmed, step out of master programming mode and set the clock to the correct time. Manually place the softener in regen. Allow the backwash to finish, then manually step through the other steps. Leave each one on just long enough to verify it is working. Allow the fast rinse to run for about 5 minutes - you will have added just a bit of brine during the brief time it was in the brine draw step and you will want to flush that out. Step into service mode and enjoy your soft water.

Add two gallons of water to your brine tank. Then add just enough salt to barely cover the water. Do not fill the brine tank - doing so will increase the possibility of salt bridge formation. Add another bag every 4 - 7 weeks ( you should use about 24 lb every 4 weeks).

My brine tank has a salt grid and based on the diameter of the tank (18x33) I'm concerned that two gallons won't cover the grid. Are my concerns unfounded?

Just add one bag of salt. Add another in about a month

OK, the softener is installed and working. I have a few more questions about programming:

1. RS my value only offers SF and rc values. Your instructions call for a FS value. Is your FS a reversed SF?

2. C unit capacity. My system has a max unit capacity (as I understand it anyway) of 32k and your recommended setting is 22.5. Why the difference?

Thank you again for your kind, expert assistance!

2. When a softener capacity is indicated at sale, it is maximum capacity. It ships with that capacity. However, running capacity is determined by salt dosage during regeneration. In order to maintain a 32k capacity on your softener you would have to regenerate with about 24 # salt per cubic ft of resin. This is extremely salt inefficient. There is a sweet spot between water efficiency (regenerating less often) and salt efficiency (regenerating with a lower salt dosage) that happens at 6 # of salt per cubic ft of resin. As salt dosage decreases, running capacity also decreases. At a 6# salt dosage, your capacity will be 22,500.

Thank you again!