How to Size a Fleck Water Softener: Grain Capacity vs. Daily Volume
Fleck system sizing starts with two numbers: your household's daily water consumption and your source water hardness in grains per gallon (GPG). The standard formula: (people × 75 gallons/day × hardness GPG) × 7 days = minimum grain capacity before regeneration. For a family of 4 with 20 GPG hardness, that's 4 × 75 × 20 × 7 = 42,000 grains — meaning a 48,000-grain 5600SXT system with comfortable headroom.
Metered vs. Timed Regeneration: Why Metered Wins
The 5600SXT uses meter-based (demand-initiated) regeneration — it counts actual gallons treated and regenerates only when the resin approaches exhaustion. Timer-based softeners (some older models) regenerate on a fixed schedule regardless of actual usage, wasting salt and water on light-use weeks. The 5600SXT's Noryl plastic meter assembly has a ~10-year life expectancy and is field-replaceable by any dealer for about $45.
Salt Dose Programming on the Fleck 5600SXT
The 5600SXT allows salt dose adjustment from 3 to 15 pounds per regeneration cycle. WQA research shows that a 6-pound dose produces roughly 3,200 grains of exchange capacity per pound of salt (20,000 grains total), while a 15-pound dose produces only 2,800 grains per pound — the salt efficiency curve diminishes sharply above 6 pounds. Programming your 5600SXT at the optimal dose (typically 6–9 lbs for residential tanks) cuts annual salt consumption by 20–35% compared to factory defaults.
Choosing a Resin Grade for Your Fleck System
Standard 8% cross-linked sulfonated polystyrene resin handles most US municipal water. High-iron water (above 3 PPM ferrous iron) requires 10% cross-linked fine-mesh resin that won't foul as quickly. Chloraminated municipal water (most US cities post-2020) requires resin formulated for chloramine exposure — ask your Fleck dealer specifically about chloramine-grade resin, which costs $20–$40 more per cubic foot but lasts 2–3 years longer in chloraminated supplies.