Tsurumi 50PN2.25S 1/3 HP Water Feature Pump – High-Head Submersible Pond & Waterfall Pump

The Tsurumi 50PN2.25S (3PN, SKU 68110) is a professional-grade, direct-drive submersible water feature pump delivering approximately 3,570 GPH at open flow (3,180 GPH at 10 feet of head) with a maximum head height of 30 feet. Rated at 1/3 HP / 529 watts / 4.6 amps, this pump is built for continuous-duty operation in ponds, waterfalls, and koi feature installations where reliability and longevity are non-negotiable. The semi-vortex fiberglass reinforced plastic (FRP) impeller passes solids and stringy debris without clogging while resisting abrasive particle wear. The 304 stainless steel casing provides maximum corrosion resistance in pond environments. A double inside mechanical seal with Silicon Carbide (SiC) faces delivers the longest seal life available. The patented Oil Lifter ensures continuous seal face lubrication using ecosystem-safe white mineral oil — not petroleum-based. B-10 rated sealed ball bearings with a 60,000-hour service life. Watertight anti-wicking cable entrance. Built-in thermal protection. 2-Year Warranty. Made in Japan. SKU 68110 | MPN 3PN | 1/3 HP | 529W | 4.6A | 115V ~3,570 GPH | 30 ft Max Head | 20 ft Cord | 2" Outlet | 9"×6"×14"H Direct Drive | FRP Impeller | 304 SS | SiC Seal | Oil Lifter | B-10 60K hr | Japan Installation note: Requires a GFCI-protected 115V outdoor outlet. Continuous-duty rated for 24/7 operation. Ideal for installation inside skimmer boxes, pump vaults, and koi pond skimmer chambers. Why Choose the Tsurumi 50PN2.25S? Direct-drive oil-free copper wound motor — continuous duty: Unlike magnetic-drive designs that lose performance more quickly as head pressure increases, the direct-drive motor maintains stronger flow through the head pressure range. Rated for 24/7 continuous operation with built-in thermal protection that shuts down before motor damage can occur. Semi-vortex FRP impeller — solids-passing without clogging: The semi-vortex design creates a vortex in the volute rather than a direct centrifugal path, allowing small solids and stringy fibrous material to pass through without contacting the impeller. FRP (Fiberglass Reinforced Plastic) construction resists wear even when abrasive particles such as sand or fine gravel are present. 304 stainless steel casing — corrosion-free in pond water: Full stainless steel outer housing resists the chlorine, mineral content, algaecides, and bio-compounds present in typical pond water environments, extending pump exterior life significantly beyond painted-iron or ABS plastic alternatives. Double inside mechanical seal with Silicon Carbide faces: SiC seal faces provide the longest operational life of any mechanical seal material currently available. The patented Oil Lifter ensures continuous lubrication of the seal faces. A V-Ring Seal Protector shields the seal from abrasive particles in the pumped water — a complete three-layer seal protection system. White mineral oil — ecosystem-safe: The oil chamber uses white mineral oil, which is non-toxic and safe for fish, koi, and aquatic plants. If any oil escapes the pump, it does not contaminate the pond ecosystem — a critical design consideration for koi ponds and water gardens. B-10 60,000-hour bearing rating: The permanently lubricated sealed ball bearings carry a B-10 life rating of 60,000 hours — meaning 90% of bearings will reach 60,000 hours without failure. At 24/7 continuous operation, that represents nearly 7 years of bearing life before statistical failure risk rises. Anti-wicking watertight cable entrance: The power cord entry point uses an anti-wicking block to prevent capillary action from drawing moisture up the cord into the motor housing — a common failure mode in cheaper pump designs. Technical Specifications Specification Detail SKU / MPN 68110 / 3PN / 50PN2.25S Horsepower 1/3 HP Max Flow (open) ~3,570 GPH (0 ft head) Max Head 30 ft Wattage 529W Amps 4.6A Voltage 115V Cord Length 20 ft (watertight anti-wicking entrance) Outlet Size 2” Dimensions 9”L × 6”W × 14”H Motor Type Direct drive, oil-free, copper wound, continuous duty Impeller Semi-vortex FRP (Fiberglass Reinforced Plastic) — solids-passing, abrasion-resistant Housing 304 Stainless Steel Mechanical Seal Double Inside Mechanical Seal with Silicon Carbide (SiC) faces Oil White mineral oil (ecosystem-safe, non-toxic to fish and aquatic life) Oil Lifter Patent-pending Oil Lifter — continuous seal face lubrication V-Ring Seal Protector Yes — protects mechanical seal from abrasive particles Bearings B-10 rated, 60,000-hour service life — permanently lubricated, sealed Thermal Protection Built-in thermal overload Installation Submersible; fits most skimmer boxes and pump vaults Electrical Requires GFCI-protected 115V outdoor outlet Warranty 2-Year Limited from date of purchase Made in Japan Performance at Head Height Flow rate decreases as head height (vertical rise plus plumbing friction) increases. Size your pump for the actual head height of your installation, not the maximum open-flow rating: Head Height Flow Rate Notes 0 ft (open flow) ~3,570 GPH Maximum with no head pressure 10 ft 3,180 GPH Typical single-level waterfall 15 ft 2,610 GPH Moderate head applications 20 ft 1,800 GPH Elevated waterfall installations 30 ft 0 GPH (max head) No flow at or beyond this height Note: Plumbing friction from tubing length, elbows, and fittings reduces effective flow rate in addition to vertical head height. Always account for total dynamic head (TDH) when sizing, not just static height. Tsurumi PN Series — Choose by HP and Flow All PN/2PU/2OM series pumps share: direct-drive construction, FRP semi-vortex impeller, 304 SS housing, SiC mechanical seal, white mineral oil, B-10 bearings, anti-wicking cable, 2-year warranty, Made in Japan. Model SKU HP GPH @ 10 ft Max Head Watts/Amps Dimensions 2OM 68100 1/5 1,980 GPH 28 ft 368W / 3.2A 8"×6"×12"H 2PU (50PU2.15S) 68105 1/5 2,880 GPH 20 ft 372W / 3.1A 9"×6"×15"H 3PN / 50PN2.25S (this) 68110 1/3 3,180 GPH 30 ft 529W / 4.6A 9"×6"×14"H 4PN (50PN2.4S) 68115 1/2 4,350 GPH 43 ft 667W / 5.8A 9"×6"×14"H 8PN (50PN2.75S) 68120 1 5,400 GPH 55 ft 1000W / 8.7A 9"×6"×15"H 12PN 68125 1 7,600 GPH 23 ft 1032W / 8.7A 12"×8"×15"H Frequently Asked Questions What is the flow rate of the Tsurumi 50PN2.25S at different head heights? The Tsurumi 50PN2.25S delivers approximately 3,570 GPH at open flow (zero head pressure). At operating head heights, performance is: 3,180 GPH at 10 feet — suitable for most single-waterfall installations 2,610 GPH at 15 feet 1,800 GPH at 20 feet Maximum head: 30 feet (no flow beyond this height) When calculating your head requirement, add vertical rise + approximately 1 foot of head for every 10 feet of horizontal pipe run, plus additional resistance for elbows and fittings. Call us at (765) 508-4352 for help calculating your system head. Is the Tsurumi 50PN2.25S safe for koi ponds and fish? Yes — the Tsurumi PN series pumps are specifically designed for ecosystem-safe operation. The oil chamber uses white mineral oil, which is non-toxic and does not harm fish, koi, or aquatic plants if it enters the water column. This is a key difference from pumps that use petroleum-based oils, which can be harmful to pond life. The stainless steel housing eliminates the risk of heavy metal leaching from cast iron or painted surfaces. All materials in contact with pond water (FRP impeller, 304 SS casing) are inert and chemically resistant to pond chemistry including pH adjusters, algaecides, and biological treatments. How does the semi-vortex FRP impeller work? The semi-vortex impeller creates a vortex pattern in the pump volute rather than a direct centrifugal path through the impeller blades. This means water and debris move through the pump without direct contact with the impeller faces — allowing small solids, leaves, twigs, and stringy algae to pass through without clogging. The Fiberglass Reinforced Plastic (FRP) construction significantly extends impeller life compared to standard plastic: when abrasive particles such as fine sand, gravel dust, or mineral deposits are present in the water (common in koi ponds and natural water features), the fiberglass composite resists wear that would degrade a standard plastic impeller within months. What makes the Tsurumi seal system different from other pumps? Tsurumi uses a three-layer seal protection system unique to their PN series: Double Inside Mechanical Seal with Silicon Carbide (SiC) faces: SiC is the hardest commercially available seal face material, providing the longest operational seal life of any configuration currently available. The double-inside design means two seals work in tandem for redundant protection. Patent-pending Oil Lifter: Continuously delivers white mineral oil to the seal faces, ensuring lubrication even during high-demand operation when conventional splash-lubricated seals run dry. V-Ring Seal Protector: A flexible elastomeric ring positioned ahead of the mechanical seal that deflects abrasive particles away from the seal face before they can cause scoring or premature wear. Together, these three components eliminate the primary failure modes of submersible pump seals: wear, dry-running, and abrasion. How long do Tsurumi pumps last, and what is the warranty? All Tsurumi PN series pumps carry a 2-year limited warranty from date of purchase. Tsurumi backs this with US-based technical support and parts availability. The design life expectations are significantly longer than the warranty period. The B-10 60,000-hour sealed ball bearing rating means that statistically, 90% of these bearings will reach 60,000 operating hours before failure — approximately 6.8 years at 24/7 continuous operation. When all three seal protection layers are intact, seal failure is correspondingly rare. Tsurumi has manufactured submersible pumps in Japan since 1952, and their PN series pumps are widely considered the professional standard for pond and waterfall applications. Will the Tsurumi 50PN2.25S fit inside a skimmer box? Yes — at 9”L × 6”W × 14”H, the 50PN2.25S fits inside most standard skimmer boxes and pump vaults. The compact form factor and 2” outlet makes plumbing straightforward with standard 2” flexible pond tubing or schedule 40 PVC. The 20-foot power cord accommodates skimmer installations with the outlet positioned away from the water feature. Note: The 14” height (taller than 2OM/2PU models) should be measured against your skimmer box interior depth before ordering. Contact us at (765) 508-4352 to confirm fitment for your specific skimmer. Why Buy Tsurumi Products from Pond Pro Direct? Authentic Tsurumi products with 2-year warranty and US-based service support Pump sizing expertise — call for head pressure calculations, skimmer compatibility checks, and PN series sizing guidance Price Match on identical products from authorized Tsurumi dealers Tsurumi 50PN2.25S (3PN, SKU 68110) — 1/3 HP | ~3,570 GPH | 30 ft max head | 529W | 4.6A | 115V | 20 ft cord | 2” outlet | 9"×6"×14"H | direct drive | FRP semi-vortex impeller | 304 SS housing | SiC double mechanical seal | Oil Lifter | V-Ring seal protector | white mineral oil | B-10 60K hr bearings | anti-wicking cable | thermal protection | 2-year warranty | Made in Japan. GFCI-protected outlet required. Questions about pump sizing, head pressure, or skimmer box compatibility? Call or text (765) 508-4352 — Monday through Friday, 9 AM to 5 PM EST.