Blue Thumb PB1793 28" Stainless Steel Formal Waterfall Spillway – Wall Mount Pond & Pool Weir for Modern Water Features

The Blue Thumb PB1793 Formal Falls® 28” is a stainless steel sheer descent weir designed to bring a smooth, glass-like curtain of water to vertical wall installations — retaining walls, garden walls, poolside features, patio backdrops, and indoor foyers. Water enters through (2) 1” FPT inlets at the rear, passes through internal baffles that eliminate turbulence, and exits over the 28” spillway lip as a smooth, uniform sheet. Pump sizing follows Blue Thumb’s specification of 100–150 GPH per inch of weir width — for the 28” weir, that means 2,800–4,200 GPH. The stainless construction is self-draining: when the pump shuts off, the weir empties automatically, eliminating freeze cracking and annual winterization. The solid full top supports courses of stacked block, stone, or tile directly above the unit. An optional color-changing LED light bar with remote (sold separately) illuminates the water sheet at night. Maximum waterfall height for a clean curtain is 24” from basin top to spillway weir. Made in the USA. 1-Year Warranty. PB1793 | 28" Spillway | 2,800–4,200 GPH | 100–150 GPH per Inch 28"W × 8"D × 3.5"H | (2) 1" FPT Inlets | Max 24" Height Self-Draining | Load-Bearing Top | Internal Baffles LED Compatible (Optional) | Made in USA | 1-Year Warranty NOT FOR USE IN SALTWATER. Do not install this weir in saltwater pools or any saltwater environment. For freshwater applications only. This listing is for the PB1793 weir unit only. Basin kit sold separately — required for a complete working installation. Not for use in saltwater applications. Why Choose the Blue Thumb Formal Falls® 28”? Smooth sheer descent waterfall effect: The PB1793’s internal baffle system diffuses incoming water pressure and eliminates turbulence before it reaches the weir lip. The result is a smooth, non-turbulent curtain of water that exits in a uniform sheet across the full 28” width — no gaps, no rippling, no streaking when the pump is properly sized. 100–150 GPH per inch sizing formula: Blue Thumb specifies the Formal Falls® flow rate as 100–150 GPH per inch of weir width. For the 28” weir: 100×28 = 2,800 GPH minimum (thin, controlled sheet) and 150×28 = 4,200 GPH maximum (full, dramatic curtain). An adjustable-flow pump is recommended to dial in your preferred water presentation between these bounds. (2) 1” FPT inlets for balanced flow: The 28” weir uses two rear inlets rather than the single inlet of the smaller 16” model. Two inlets provide more balanced water distribution across the wider spillway, reducing dead spots and ensuring even sheet presentation. If running a single pump, cap the unused second inlet. Solid load-bearing top: The full solid top of the weir housing supports multiple courses of stacked block, stone, or tile installed directly above the unit. The weir is designed to integrate flush with standard 8” block-wall systems, with the solid top carrying the weight of the wall above it structurally. Self-draining — no winterization required: The stainless housing drains completely when the pump shuts off. No annual drain-down procedure, no compressed air blowout, no risk of freeze cracking. In cold climates, simply shut off the pump before freezing temperatures arrive and the weir empties on its own. Maximum waterfall height — 24”: For a clean, unbroken sheer descent, Blue Thumb specifies a maximum drop of 24” from basin water surface to the spillway weir. At greater heights, the falling water sheet can break apart, aerate, and produce mist rather than the clean curtain effect. Design your wall height with this specification in mind. Compatible with retaining wall block systems: The PB1793 is engineered to work with most major retaining wall block manufacturers. The 8” depth fits standard block cavity dimensions, and the solid top allows wall courses to be built directly above without requiring headers or lintels for normal wall heights. Optional LED color-changing light (sold separately): The Blue Thumb LED Light Bar with remote control (sold separately) mounts behind the water sheet to illuminate the falling curtain in a full spectrum of colors. The compact profile allows installation without altering the wall opening dimensions. Technical Specifications Specification Detail SKU PB1793 Spillway Width 28 inches Dimensions (W × D × H) 28” × 8” × 3.5” Suggested Flow Rate 2,800–4,200 GPH (100–150 GPH per inch of weir width) Inlets (2) 1” FPT threaded inlets (rear) Material Stainless steel Internal Baffles Yes — eliminates turbulence for smooth sheet effect Self-Draining Yes — no winterization required Max Waterfall Height 24” from basin water surface to spillway weir Top Structure Solid full top — supports stacked block, stone, or tile LED Lighting Optional — sold separately (Blue Thumb color-changing LED bar) Basin Sold separately — weir unit only (basin required for complete install) Saltwater NOT approved — freshwater only Made in USA Warranty 1-Year Warranty Formal Falls® Family — Select by Wall Width All Formal Falls® weirs share: stainless steel construction, internal baffle system, self-draining design, solid load-bearing top, 8” depth × 3.5” height housing, 100–150 GPH per inch flow rate, 24” maximum waterfall height, Made in USA, 1-Year Warranty, not for saltwater. Inlet count scales with spillway width. Model SKU Width Suggested Flow Inlets Dimensions (W×D×H) Small Formal Falls® PB1779 16" 1,600–2,400 GPH 1 × 1" FPT 16"×8"×3.5" Medium Formal Falls® (this) PB1793 28" 2,800–4,200 GPH 2 × 1" FPT 28"×8"×3.5" Large Formal Falls® PB1816 40" 4,000–6,000 GPH 3 × 1" FPT 40"×8"×3.5" Frequently Asked Questions What is the recommended pump flow rate for the 28" Formal Falls®? Blue Thumb specifies 100–150 GPH per inch of weir width for all Formal Falls® models. For the 28” weir, that means: 2,800 GPH minimum (100 GPH × 28”) — produces a thin, controlled sheet 4,200 GPH maximum (150 GPH × 28”) — produces a full, dramatic curtain An adjustable-flow pump is strongly recommended so you can dial in your preferred water presentation between the 2,800 and 4,200 GPH range. For a standard residential installation at mid-height, 3,000–3,500 GPH typically produces a beautiful, well-defined sheet. Note that this is the flow rate delivered at the weir — account for pipe friction losses and head pressure based on your pump placement and plumbing run length when sizing your pump. Call (765) 508-4352 for pump sizing assistance. Is this spillway suitable for saltwater or chlorinated pool applications? The Blue Thumb PB1793 is not approved for use in saltwater applications. Do not install this weir in a saltwater pool environment. For freshwater applications including chlorinated residential pools and water features, the stainless steel construction is appropriate. Regular cleaning and occasional descaling (to prevent calcium and mineral buildup on the spillway face) will maintain the polished appearance over time. How does the internal baffle system improve the waterfall display? Water entering the rear inlets of the PB1793 arrives under pump pressure — which, without a distribution system, would create turbulence and uneven flow across the 28” weir face. The internal baffles spread incoming flow evenly across the full width of the housing, dissipating pressure and equalizing the water depth behind the spillway lip before it exits. The result is a non-turbulent, uniform sheet across the full 28” spillway — the glass-like “sheer descent” effect. For best results, set your maximum waterfall height at no more than 24” from basin water surface to the spillway weir. At greater heights, even a well-distributed sheet can begin to break apart and aerate during the fall. Can I add LED lighting to the Blue Thumb 28" Formal Falls®? Yes. The PB1793 is compatible with Blue Thumb’s color-changing LED Light Bar with remote control, available as a separate add-on. The light bar installs behind the water sheet inside the wall opening, illuminating the falling curtain in your choice of colors from the included remote. The LED light bar is not included with the PB1793 weir unit. If lighting is important to your design, order the LED light bar as a companion item at the same time. Contact (765) 508-4352 for current LED bar pricing and compatibility confirmation. What are the installation requirements for this spillway? The PB1793 features (2) 1” FPT (Female Pipe Thread) inlets at the rear for standard plumbing connections. If running a single pump, cap the second inlet using a standard 1” MPT plug. For larger flow rates or balanced distribution across the full 28” width, a split-flow configuration using both inlets is recommended. Installation dimensions: the unit is 28” wide × 8” deep × 3.5” tall. The 8” depth fits standard 8” block wall systems. The solid full top supports stacked block, stone, or tile courses above the unit without requiring a separate lintel for normal wall heights. The basin (sold separately) should be positioned so the water surface is no more than 24” below the spillway weir for a clean, unbroken sheet. Mount the weir level — even a slight tilt will shift the water sheet to one side. Why Buy Blue Thumb Products from Pond Pro Direct? Authentic Blue Thumb products with 1-Year Warranty and USA manufacturing Formal water feature expertise — call for help sizing your pump, selecting your basin, and designing the complete installation Price Match on identical Blue Thumb products from authorized retailers Blue Thumb PB1793 Formal Falls® 28” — 2,800–4,200 GPH (100–150 GPH per inch) | 28”×8”×3.5” | (2) 1” FPT inlets | self-draining | 24” max waterfall height | solid load-bearing top | LED compatible (sold separately) | Made in USA | 1-Year Warranty. NOT for saltwater. Basin sold separately. Questions about pump sizing, basin selection, or complete formal waterfall design? Call or text (765) 508-4352 — Monday through Friday, 9 AM to 5 PM EST.