Water softening salt
APEC softeners are compatible with solar evaporated salt pellets, evaporated salt pellets, or rock salt at a minimum purity of 99.5% NaCl. Solar salt pellets (Diamond Crystal Solar Naturals, Morton Solar Salt) are a good all-purpose choice at $6-10 per 40-pound bag. Avoid salt with iron inhibitor additives if source iron is below 0.3 PPM -- these additives are not needed and can leave a residue in the brine tank. Add salt when the brine tank is less than one-third full. Never allow the brine tank to run empty (dry regeneration reduces resin capacity). At a 48,000-grain system with 8 lbs salt per regeneration and 10-day intervals, monthly salt consumption runs 24-32 lbs.
Ion-exchange resin
The high-capacity sulfonated polystyrene cation exchange resin in APEC softeners has a designed service life of 10-15 years under normal operating conditions. Resin degradation accelerates in the presence of chlorine above 1 PPM (a common municipal water disinfectant) and iron above 3 PPM. If output hardness begins breaking through at shorter intervals than the programmed capacity predicts, resin replacement restores the system to full capacity. Standard 8% crosslink cation exchange resin is available from water treatment suppliers for $60-100 per cubic foot. The APEC 48,000-grain system uses 1.5 cubic feet. Resin replacement requires draining the tank, removing the control valve, and refilling with fresh resin.
Control valve components
APEC control valves are manufactured by Fleck (a Pentair brand) or compatible equivalents, depending on model year. Fleck 5600SXT or 5600SE control valve seals and spacers kits (part 60120-10) replace the wear items in the piston assembly and are available for $15-25 from water treatment suppliers. The injector and cap assembly (Fleck part 13108 for standard injectors) controls brine draw during regeneration -- replace if the softener fails to draw brine (white salt remains in brine tank after regeneration). Injectors are model-size specific; confirm the injector size (marked A, B, C, D on the cap) before ordering.
Brine tank components
The brine valve assembly (safety float and brine valve) inside the APEC brine tank prevents overfill and controls brine concentration. Replace the brine valve if water is overflowing the brine tank or if the tank runs dry before regeneration completes. Standard Fleck-compatible brine valve assemblies cost $15-30. The brine tank itself is a polyethylene vessel with a 15-20 year service life under normal conditions. Inspect annually for cracks along the seam at the base. A salt bridge (hardened salt layer above an empty cavity) can form in humid environments; break it with a broom handle and reduce salt fill levels to prevent recurrence.