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Top Mount FRP Tanks - 4" NPSM Series

This series features high-capacity FRP tanks with a standard 4" NPSM threaded top opening. Engineered for demanding applications, these tanks are the preferred choice for commercial, light industrial, and high-flow residential water treatment systems utilizing 4" control valves.

This series features high-capacity FRP tanks with a standard 4" NPSM threaded top opening. Engineered for demanding applications, these tanks are the preferred choice for commercial, light industrial, and high-flow residential water treatment systems utilizing 4" control valves.

Elevate Your Commercial Water Treatment with 4" NPSM Tanks

For larger commercial facilities, light industrial applications, or high-demand residential systems, the standard 2.5" connection simply isn't enough. Stark Water's 4" NPSM Series FRP tanks are designed to meet these increased flow requirements without compromising on durability or reliability.

As a trusted B2B partner, we provide system integrators, large installers, and OEMs with tanks that are not only robust but also perfectly compatible with the advanced control valves used in high-capacity systems.

Key Advantages for High-Flow Applications

When system performance is critical, our 4" NPSM tanks deliver:

  • Optimized for Higher Flow Rates
    The 4" NPSM opening significantly increases the head room and reduces pressure drop, making these tanks ideal for applications requiring higher flow rates in filtration and softening.
  • Robust & Reliable Valve Connection
    Our precision-molded 4" NPSM threaded opening ensures a secure, leak-free connection with larger commercial control valves (e.g., Aquamatic, Autotrol, Fleck Commercial). This specialized design prevents compatibility issues and guarantees system integrity.
  • Uncompromising Corrosion Resistance
    Built with a seamless, food-grade HDPE inner liner and reinforced with high-strength fiberglass filament winding, these tanks are 100% corrosion-proof. This extends the lifespan of your systems, even in challenging water conditions.
  • Engineered for Commercial Longevity
    Each tank is rigorously manufactured to withstand the demands of continuous commercial operation:

    • Rated for 150 PSI (10 bar) operating pressure.
    • Cycle-tested to **over 300,000 cycles** for maximum durability.
    • 100% factory pressure-tested before shipment to ensure zero defects.
    • (Optional: NSF/ANSI Certified for material safety and structural integrity, if applicable.)

Ideal for Commercial & Industrial Systems

This 4" NPSM series is the perfect solution for:

  • Commercial Water Softeners & Filters
  • Industrial Pre-treatment Systems
  • Hotels, Resorts, and Large Residential Complexes
  • Municipal Water Treatment (smaller scale applications)
  • Deionization (DI) and Reverse Osmosis (RO) Pre-treatment

Explore Other FRP Tank Series

This page features our 4" NPSM models. For different connection types or applications, explore our other product lines:

Below are the corrected and verified specifications for our 4" NPSM top-mount series. These high-flow tanks are designed for commercial and industrial applications. Find your required model by US Gallons (Gal) or Liters (L), and Dimensions.

Model Volume Dimensions (Dia x H) Flow Rate (m³/h) Request a Quote
US (Gal) Metric (L) Nominal (in) Actual (mm) (Filter/Softener)
STK-1465 38.6 146 14" x 65" Ø355 x 1670 1.2-2.3 Inquiry
STK-1665 49.7 188 16" x 65" Ø400 x 1670 1.5-3.8 Inquiry
STK-1865 62.9 238 18" x 65" Ø450 x 1670 2.5-4.7 Inquiry
STK-2162 83.5 316 21" x 62" Ø530 x 1780 3.0-6.0 Inquiry
STK-2472 109.6 415 24" x 72" Ø600 x 1920 4.2-8.4 Inquiry
STK-3072 169.1 640 30" x 72" Ø750 x 1920 6.6-13.0 Inquiry
STK-3672 264.2 1000 36" x 72" Ø900 x 2150 9.5-19.0 Inquiry

*Note: Specifications are based on standard product data. US dimensions are nominal. Flow rates are estimates; please consult our engineers for precise system design.

The 4" NPSM series is the "high-flow workhorse" of our lineup. It bridges the gap between residential and heavy industrial tanks, making it the perfect choice for commercial facilities that require consistent, high-volume water delivery.

1. Commercial Hospitality (Hotels & Resorts)

Hotels and resorts demand uninterrupted soft water for guest showers, laundry services, and boiler protection. Our 4" tanks handle these peak flow rates efficiently, preventing pressure drops during morning rush hours.

2. Industrial RO Pre-treatment

Essential for protecting sensitive Reverse Osmosis (RO) membranes. These tanks are widely used as Multi-Media Filters (MMF) or Activated Carbon Filters to remove silt, chlorine, and organics before the water enters commercial RO units.

3. Agricultural Irrigation & Farming

Ideal for high-volume well water filtration. They effectively filter out sand and sediment that can clog drip irrigation nozzles, ensuring uniform water distribution for crops and greenhouses.

4. Institutional Facilities (Schools & Hospitals)

Institutions require 100% reliability. Our 4" NPSM tanks provide the structural integrity and capacity needed for centralized water softening and filtration in large public buildings.

Build Your Complete Commercial System

Looking for 4" control valves, commercial distributors, or UV sterilizers?

Source all your matching system components directly from our equipment division:

→ Visit Stark-Water.com for Commercial Equipment

Elevate Your Commercial Water Treatment with 4" NPSM Tanks

For larger commercial facilities, light industrial applications, or high-demand residential systems, the standard 2.5" connection simply isn't enough. Stark Water's 4" NPSM Series FRP tanks are designed to meet these increased flow requirements without compromising on durability or reliability.

As a trusted B2B partner, we provide system integrators, large installers, and OEMs with tanks that are not only robust but also perfectly compatible with the advanced control valves used in high-capacity systems.

Key Advantages for High-Flow Applications

When system performance is critical, our 4" NPSM tanks deliver:

  • Optimized for Higher Flow Rates
    The 4" NPSM opening significantly increases the head room and reduces pressure drop, making these tanks ideal for applications requiring higher flow rates in filtration and softening.
  • Robust & Reliable Valve Connection
    Our precision-molded 4" NPSM threaded opening ensures a secure, leak-free connection with larger commercial control valves (e.g., Aquamatic, Autotrol, Fleck Commercial). This specialized design prevents compatibility issues and guarantees system integrity.
  • Uncompromising Corrosion Resistance
    Built with a seamless, food-grade HDPE inner liner and reinforced with high-strength fiberglass filament winding, these tanks are 100% corrosion-proof. This extends the lifespan of your systems, even in challenging water conditions.
  • Engineered for Commercial Longevity
    Each tank is rigorously manufactured to withstand the demands of continuous commercial operation:

    • Rated for 150 PSI (10 bar) operating pressure.
    • Cycle-tested to **over 300,000 cycles** for maximum durability.
    • 100% factory pressure-tested before shipment to ensure zero defects.
    • (Optional: NSF/ANSI Certified for material safety and structural integrity, if applicable.)

Ideal for Commercial & Industrial Systems

This 4" NPSM series is the perfect solution for:

  • Commercial Water Softeners & Filters
  • Industrial Pre-treatment Systems
  • Hotels, Resorts, and Large Residential Complexes
  • Municipal Water Treatment (smaller scale applications)
  • Deionization (DI) and Reverse Osmosis (RO) Pre-treatment

Explore Other FRP Tank Series

This page features our 4" NPSM models. For different connection types or applications, explore our other product lines:

Below are the corrected and verified specifications for our 4" NPSM top-mount series. These high-flow tanks are designed for commercial and industrial applications. Find your required model by US Gallons (Gal) or Liters (L), and Dimensions.

Model Volume Dimensions (Dia x H) Flow Rate (m³/h) Request a Quote
US (Gal) Metric (L) Nominal (in) Actual (mm) (Filter/Softener)
STK-1465 38.6 146 14" x 65" Ø355 x 1670 1.2-2.3 Inquiry
STK-1665 49.7 188 16" x 65" Ø400 x 1670 1.5-3.8 Inquiry
STK-1865 62.9 238 18" x 65" Ø450 x 1670 2.5-4.7 Inquiry
STK-2162 83.5 316 21" x 62" Ø530 x 1780 3.0-6.0 Inquiry
STK-2472 109.6 415 24" x 72" Ø600 x 1920 4.2-8.4 Inquiry
STK-3072 169.1 640 30" x 72" Ø750 x 1920 6.6-13.0 Inquiry
STK-3672 264.2 1000 36" x 72" Ø900 x 2150 9.5-19.0 Inquiry

*Note: Specifications are based on standard product data. US dimensions are nominal. Flow rates are estimates; please consult our engineers for precise system design.

The 4" NPSM series is the "high-flow workhorse" of our lineup. It bridges the gap between residential and heavy industrial tanks, making it the perfect choice for commercial facilities that require consistent, high-volume water delivery.

1. Commercial Hospitality (Hotels & Resorts)

Hotels and resorts demand uninterrupted soft water for guest showers, laundry services, and boiler protection. Our 4" tanks handle these peak flow rates efficiently, preventing pressure drops during morning rush hours.

2. Industrial RO Pre-treatment

Essential for protecting sensitive Reverse Osmosis (RO) membranes. These tanks are widely used as Multi-Media Filters (MMF) or Activated Carbon Filters to remove silt, chlorine, and organics before the water enters commercial RO units.

3. Agricultural Irrigation & Farming

Ideal for high-volume well water filtration. They effectively filter out sand and sediment that can clog drip irrigation nozzles, ensuring uniform water distribution for crops and greenhouses.

4. Institutional Facilities (Schools & Hospitals)

Institutions require 100% reliability. Our 4" NPSM tanks provide the structural integrity and capacity needed for centralized water softening and filtration in large public buildings.

Build Your Complete Commercial System

Looking for 4" control valves, commercial distributors, or UV sterilizers?

Source all your matching system components directly from our equipment division:

→ Visit Stark-Water.com for Commercial Equipment