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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 full specifications for our 4" NPSM top-mount series. Find your required model by US Gallons (Gal) or Liters (L), and US standard dimensions (Inches) or Metric (mm). Click "Request a Quote" for fast, accurate B2B pricing.

Model Volume Nominal Dimensions Flow Rate (m³/h) Request a Quote
US (Gal) Metric (L) US (in) (D x H) Metric (mm) (D x H) (Filter/Softener)
STK-1865 26.2 99 18" x 65" Ø450 x 1670 2.5-4.5 Inquiry
STK-2162 34.3 130 21" x 62" Ø525 x 1580 3.5-6.0 Inquiry
STK-2472 47.6 180 24" x 72" Ø600 x 1820 5.0-8.5 Inquiry

*Note: US dimensions (inches) are nominal. Please refer to metric dimensions (mm) for exact engineering specifications. Flow rates are estimates; consult our engineers for system design verification.

  • Commercial Water Softeners
  • Commercial & Light Industrial Filtration
  • Hotels, Resorts, and Multi-Family Residential
  • Institutional Water Treatment (Schools, Hospitals)
  • Industrial Pre-treatment for RO/DI
  • Food & Beverage Processing
  • Agriculture & Irrigation Systems

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 full specifications for our 4" NPSM top-mount series. Find your required model by US Gallons (Gal) or Liters (L), and US standard dimensions (Inches) or Metric (mm). Click "Request a Quote" for fast, accurate B2B pricing.

Model Volume Nominal Dimensions Flow Rate (m³/h) Request a Quote
US (Gal) Metric (L) US (in) (D x H) Metric (mm) (D x H) (Filter/Softener)
STK-1865 26.2 99 18" x 65" Ø450 x 1670 2.5-4.5 Inquiry
STK-2162 34.3 130 21" x 62" Ø525 x 1580 3.5-6.0 Inquiry
STK-2472 47.6 180 24" x 72" Ø600 x 1820 5.0-8.5 Inquiry

*Note: US dimensions (inches) are nominal. Please refer to metric dimensions (mm) for exact engineering specifications. Flow rates are estimates; consult our engineers for system design verification.

  • Commercial Water Softeners
  • Commercial & Light Industrial Filtration
  • Hotels, Resorts, and Multi-Family Residential
  • Institutional Water Treatment (Schools, Hospitals)
  • Industrial Pre-treatment for RO/DI
  • Food & Beverage Processing
  • Agriculture & Irrigation Systems

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