How to Choose Between 4040 & 8040 Membranes
Ultimate Guide to RO Membranes 4040 & 8040 (2025 Update)
4040 vs 8040 RO Membranes: Key Differences
✔ Size Comparison:
• 4040: 4" diameter x 40" length
• 8040: 8" diameter x 40" length
✔ Flow Rates:
• 4040: 2,500-3,500 GPD
• 8040: 8,000-12,000 GPD
✔ Applications:
• 4040: Small commercial/light industrial
• 8040: Large industrial/municipal
Technical Specifications Comparison
| Parameter | 4040 Membrane | 8040 Membrane |
|---|---|---|
| Active Area | 85-100 ft² | 365-400 ft² |
| Max Pressure | 600 psi | 600 psi |
| pH Range | 2-11 | 2-11 |
| Temp Range | 41-113°F | 41-113°F |
| Salt Rejection | 99.7% | 99.7% |
Top 5 Applications
1. Drinking Water Systems
• Small communities (8040)
• Restaurants/hotels (4040)
2. Industrial Process Water
• Boiler feed water
• Cooling tower makeup
3. Wastewater Reuse
• Car washes
• Textile factories
4. Food & Beverage
• Bottled water production
• Brewery water treatment
5. Medical Facilities
• Dialysis water
• Laboratory pure water
Installation & Maintenance Tips
Proper Installation Steps
1. Lubricate O-rings with glycerin
2. Align membrane correctly
3. Follow manufacturer torque specs
4. Perform initial flush (30 mins)
Maintenance Schedule
• Daily: Monitor pressure drop
• Weekly: Check permeate quality
• Monthly: Clean in place (CIP)
• Annually: Professional inspection
Troubleshooting Common Issues
⚠️ Reduced Flow Rate?
• Cause: Fouling/scaling
• Fix: Clean with pH 2-11 solution
⚠️ High Pressure Drop?
• Cause: Biofilm buildup
• Fix: Disinfect with 1% hydrogen peroxide
⚠️ Poor Salt Rejection?
• Cause: O-ring failure
• Fix: Replace all seals
Extending Membrane Life
Do:
✔ Maintain proper crossflow velocity
✔ Use antiscalant chemicals
✔ Follow cleaning protocols
Don't:
✖ Exceed max pressure
✖ Allow chlorine contact
✖ Operate outside pH range
