The Fleck 5600SXT is the most widely installed water softener in the United States. Metered regeneration, rock-solid Pentair valve, and decades of proven performance. Here's the complete picture.
The Fleck 5600SXT earns its reputation. Demand-initiated metered regeneration means it only regenerates when needed — saving salt and water vs timer-based systems. The SXT digital control head is programmable, reliable, and available in 32,000–80,000 grain sizes for any household. The main caveat: Fleck is sold through dealers and online retailers, not direct — you need to find a reputable seller.
| Control valve | Fleck 5600SXT — Pentair manufactured |
| Regeneration type | Metered demand-initiated — regenerates based on water use, not a timer |
| Available grain capacities | 32,000 / 48,000 / 64,000 / 80,000 grain |
| Flow rate | Up to 12 GPM service flow |
| Salt efficiency | ~6 lbs salt per 1,000 grains removed (industry leading) |
| Brine tank | Separate brine (salt) tank included |
| Display | Digital LCD — programmable |
| Bypass valve | Manual bypass included |
| Iron removal | Up to ~3 PPM ferrous iron (limited — use dedicated iron filter for higher levels |
| Power | 110V AC |
| Warranty | 5 years on control valve, 10 years on tanks |
Older timer-based softeners regenerate on a fixed schedule — every 3 days, every week — regardless of how much water you've actually used. If you go on vacation for a week, it still regenerates. If you have guests and use 3x normal water, it doesn't regenerate until the timer says so.
The 5600SXT's metered system tracks actual gallons used and regenerates only when the resin bed is approaching capacity. For most households this means 20–40% less salt and water usage compared to timer-based systems. Over a year that's real money.
The "SXT" designation refers to the digital control head. It replaced the older mechanical 5600 timer head and is now the standard. Key features:
| 32,000 grain | 1–2 people, moderately hard water (up to ~25 GPG) |
| 48,000 grain | 2–4 people — most common residential choice |
| 64,000 grain | 4–6 people, or smaller households with very hard water |
| 80,000 grain | Large families, very hard water, or high iron content |
Size calculation: multiply your household's daily water use (gallons) by water hardness (GPG). Example: 4 people × 75 gallons/day = 300 gallons/day × 20 GPG hardness = 6,000 grains/day. A 48,000 grain softener regenerates every 8 days. Size up if you have iron — iron consumes resin capacity.
The 5600SXT handles well water but with important limitations. It removes ferrous (dissolved) iron up to about 3 PPM as a secondary benefit of the ion exchange process. If your well water iron is above 3 PPM, you need a dedicated iron filter upstream — the Springwell WF1 or an air injection filter — before the softener.
Running high iron through a softener without pre-treatment will foul the resin bed, reducing softening capacity and shortening the resin life significantly.
Get your water tested before buying. You need hardness (GPG), iron (PPM), and pH. If iron is above 3 PPM, install an iron filter upstream. If pH is below 7.0, add an acid neutralizer. The 5600SXT is excellent once the water is properly pre-treated.
Fleck doesn't sell direct. The 5600SXT is sold through authorized dealers and online retailers. Quality varies significantly — some Amazon listings include poorly matched resin tanks or incorrect media. Reputable sources: