Tucker Max-Flow (Variable Flow): ≥80% rejection is acceptable. Optimal pressure is 40-80 PSI, but can safely handle up to 120 PSI.
Triton XLP-4040 (High Pressure): ≥85% rejection is acceptable in the field. While optimal pressure is 80+ PSI, it can operate at pressures down to 40 PSI, though flow rates will be reduced.
Common factors that impact rejection & flow:
Operating Temperature: RO membranes are factory rated at 25°C (77°F). As water gets colder, it becomes more viscous. Expect a 2% to 3% drop in water production for every degree Celsius below 25°C.
Water Source (City vs Well): Well water contains iron and sediment that rapidly clogs membranes. Use a dedicated sediment or KDF/Carbon filter. City water contains chlorine, which destroys membranes if the carbon block isn't changed regularly.
Pressure at the membrane: Matching membrane type to your tap pressure is critical. Low pressure drops both flow rate and rejection efficacy.
Troubleshooting Spotting (When PPM is 0-10)
If your system tests perfect but spots remain on the glass, the issue is external:
Soap Bleed / Oxidation: Pure water is a hungry solvent. It will pull old soap residue or oxidized aluminum chalkiness out from under the top frame seals. Rinse frames aggressively before your final glass rinse.
Hydrophobic Glass: Some glass repels water into beads instead of sheeting. These beads trap microscopic dirt. Scrub thoroughly and rinse top-down slowly.
Pre-existing Stains: Pure water will not remove baked-on hard water or calcium stains. Those require chemical stain removers.
Pass/Fail Targets
RO Efficacy = ((TAP − RO) / TAP) × 100
≥ 80% = Normal (85% for Triton)
75–79% = Low → plan to replace
< 75% = Critically low → replace now
DI PPM
0–10 ppm = Excellent (Spot-Free)
11–20 ppm = Marginal → replace soon
> 20 ppm = Replace DI
Diagnostic Flow
No flush flow? Slightly open the flush valve:
If flow appears → replace the flush valve.
If still no flow → replace the RO membrane.
Low pressure? Check for leaks at carbon/DI housings and fittings. If none, replace the carbon/combo filter.
