The SXT digital head is programmable and powerful — once you know what the settings mean. Here's every setting you need to configure for proper operation.
Get your water tested or use a test kit before programming. Hardness in grains per gallon (GPG) and iron in PPM are the two inputs that drive every other setting. Without accurate numbers, your softener will either over-soften (wasting salt) or under-soften (leaving hard water).
| Time of Day | Set current time — regeneration occurs at the time set in "Regeneration Time" below |
| Regeneration Time | Default: 2:00 AM — when regeneration runs. Set to a time when water is not in use. Most homeowners leave this at 2 AM. |
| Hardness (H) | Enter your water hardness in GPG. If you have iron, add 3–5 GPG per 1 PPM of iron (iron compensation). Example: 20 GPG hardness + 2 PPM iron = set to 26. |
| Iron Compensation | Some programming versions have a separate iron setting. Add 3 GPG per PPM of iron to your hardness number if no separate setting. |
| Day Override (DO) | Maximum days between regenerations. Default: 14. Most installs: 7–10. This forces regeneration even if metered capacity hasn't been reached — prevents resin from sitting too long. |
| Regeneration Type (SF) | Leave at default "Immediate" for most installs. Delayed means it waits until the set time even if capacity is hit during the day. |
| Reserve Capacity | Percentage of capacity held in reserve for use during regeneration cycle. Default: 25%. Increase to 35% for larger households. |
This is where most people make mistakes. Your softener needs to know the total "load" it's treating — hardness plus the effective hardness impact of iron.
The standard formula: Effective Hardness = Actual Hardness GPG + (Iron PPM × 3)
Example: Water test shows 18 GPG hardness and 2 PPM iron. Effective hardness = 18 + (2×3) = 24 GPG. Enter 24 in the hardness setting.