Blue Thumb PB1120 Large Elite Cascade Falls Spillway Box – Pondless Waterfall Kit Filter – 22" Weir for DIY Pond Builds

The Blue Thumb PB1120 Large Elite Cascade Falls Box is a 30” spillway waterfall box engineered for Pond-Less waterfalls and traditional pond installations requiring high-flow, professional-quality water presentation. With a maximum pump rating of 7,500 GPH and a full-width black Matala diffuser mat that creates a smooth, even sheet of water across the complete 30” weir, the PB1120 is a contractor-grade Pond-Less head unit built to last. Dimensions: 20”L × 41”W × 14.25”H. Connects via two factory-installed 3” spinweld fittings. Rated for ponds up to 6,000 gallons. Place two units side-by-side for a 60” combined spillway width. Made in the USA. Lifetime Warranty. PB1120 | 30" Spillway | 7,500 GPH Max | Pond-Less & Pond Applications 20"L × 41"W × 14.25"H | Two 3" Spinweld Inlets | Max 6,000 Gal Black Matala Diffuser Mat | Detachable & Reversible Weir | SS Hardware Side-by-Side Expandable | Made in USA | Lifetime Warranty Size note: The PB1120 is the 30” Large model. For a 22” spillway see the Medium Elite Cascade Falls Box (5,500 GPH). For 40” see the Extra Large (10,000 GPH). All models share the same Lifetime Warranty, Made in USA construction, and identical included accessories. Why Choose the Blue Thumb PB1120? 30” smooth waterfall sheet — black Matala diffuser mat included: The included black Matala mat sits inside the box and distributes incoming pump water evenly across the full 30” weir opening. Water exits in a smooth, uniform curtain without gaps, turbulence, or uneven flow — eliminating the “churning” effect produced by simpler waterfall boxes without internal distribution media. 7,500 GPH maximum pump flow: The PB1120 is engineered for pump flow up to 7,500 GPH — ideal for medium-to-large Pond-Less waterfalls and traditional pond waterfall heads. Use a pump rated within this flow range for best waterfall presentation. Two 3” factory-installed spinweld fittings accept standard PVC flex hose from the pump vault. Side-by-side expandable for custom widths: Two PB1120 units placed side-by-side create a 60” combined spillway. This modular design allows you to build any waterfall width from 30” up, and is a key feature of the Blue Thumb Cascade Falls Box design across all sizes. Detachable and reversible weir: The weir (the lip water flows over) is detachable for installation convenience — simplifying liner work during construction — and reversible to adjust the waterfall presentation. Stainless steel self-tapping screws secure all hardware, resisting corrosion through years of outdoor use. Landscape lid for natural concealment: The included landscape lid covers the top of the box, allowing rocks, gravel, or ground cover to be placed over the unit for a natural, fully concealed installation. The box disappears into the landscape while the waterfall remains fully functional. Contractor-grade construction — Lifetime Warranty: Built from reinforced contractor-grade material designed to withstand the load of heavy boulders and long-term outdoor exposure. Blue Thumb backs the PB1120 with a Lifetime Warranty and manufactures it in the USA. Compatible with Blue Thumb LED Light Bars: Add color-changing LED lighting (sold separately) to illuminate the 30” waterfall curtain at night for a dramatic display controllable by remote. What’s Included Landscape lid (for concealing box under rocks and gravel) Black Matala diffuser mat (for smooth, even water dispersion over the 30” weir) Two factory-installed 3” spinweld fittings (inlet connections for PVC flex hose) Detachable and reversible weir Self-tapping stainless steel screws Black silicone (for waterproofing hardware penetrations) Plumbing fittings Full color installation instructions Technical Specifications Specification Detail SKU PB1120 Waterfall Width 30” spillway Max Pump Flow 7,500 GPH Max Pond Volume 6,000 gallons Dimensions 20”L × 41”W × 14.25”H Inlet Two 3” factory-installed spinweld fittings Weir Detachable and reversible Diffuser Black Matala mat (even water distribution) Hardware Stainless steel self-tapping screws (corrosion resistant) Side-by-Side Yes — expandable waterfall widths LED Compatible Yes (Blue Thumb LED Light Bars, sold separately) Application Pond-Less waterfalls, traditional ponds, streams Made In USA Warranty Lifetime Warranty Elite Cascade Falls Box Family — Select by Waterfall Width All Elite Cascade Falls Box sizes share: black Matala diffuser mat, landscape lid, detachable/reversible weir, stainless steel hardware, factory-installed spinweld fittings, plumbing fittings, full color instructions, Made in USA, Lifetime Warranty, Pond-Less and traditional pond compatible, side-by-side expandable. Model SKU Weir Width Max GPH Dimensions (L×W×H) Small Elite Cascade Box PB1106 14" 2,500 GPH 19"×24"×14.25" Medium Elite Cascade Box — 22" 5,500 GPH 20"×33"×14.25" Large Elite Cascade Box (this) PB1120 30" 7,500 GPH 20"×41"×14.25" Extra Large Elite Cascade Box — 40" 10,000 GPH 19.5"×51"×14.25" Frequently Asked Questions What is the weir width and maximum flow rate for the PB1120? The Blue Thumb PB1120 Large Elite Cascade Falls Box features a 30” spillway weir and is rated for pump flows up to 7,500 GPH maximum. For a smooth, well-formed waterfall sheet, a pump in the 5,000–7,500 GPH range at your actual installation head height is ideal. The included black Matala diffuser mat distributes incoming pump water evenly across the full 30” width before it flows over the weir, producing a consistent curtain without gaps or turbulence. For a wider combined spillway, place two PB1120 units side-by-side for a 60” waterfall width. How does the internal mat system improve the waterfall? The included black Matala diffuser mat sits inside the box and acts as a distribution medium. As pump water enters through the two 3” spinweld fittings, it spreads horizontally through the Matala mat before flowing over the weir. This distributes water evenly across the full 30” spillway width, preventing the “rushing to center” effect that creates narrow, turbulent waterfalls in boxes without internal distribution media. The Matala mat also provides minor mechanical filtration, trapping larger debris as water passes through. For dedicated biological or mechanical pond filtration, a separate waterfall filter box is recommended — the Cascade Falls Box is designed for waterfall presentation, not as a primary pond filter. What makes the Elite Series more durable than standard waterfall boxes? The Elite Cascade Falls Box uses contractor-grade reinforced construction engineered to withstand the compressive weight of heavy boulders placed on and around it during landscape installation. All hardware is stainless steel, resisting corrosion through years of continuous outdoor operation. Blue Thumb backs the PB1120 with a Lifetime Warranty and manufactures it in the USA. Can this box be used for biological filtration? The Elite Cascade Falls Box is designed as a waterfall presentation and Pond-Less head unit, not as a dedicated biological filter. The included black Matala mat provides some mechanical filtration as water passes through, but it is optimized for even water dispersion over the weir — not for the colonization of biological filter media. For biological filtration in a traditional pond, pair the Cascade Falls Box with a dedicated waterfall filter box upstream, or use the Cascade Falls Box as the final waterfall head at the end of a stream with a biological filter box at the stream source. Is this waterfall box compatible with LED lighting? Yes. The PB1120 is designed to accommodate Blue Thumb LED Light Bars (sold separately). LED light bars can be positioned to illuminate the 30” water curtain from inside the box, creating a dramatic color-changing nighttime display controlled by remote or smartphone app depending on the light bar model you select. Why Buy Blue Thumb Products from Pond Pro Direct? Authentic Blue Thumb products — Lifetime Warranty, Made in USA Waterfall sizing expertise — call for help matching pump flow, basin size, and stream design to the PB1120 Price Match on identical Blue Thumb products from authorized retailers Blue Thumb PB1120 Large Elite Cascade Falls Box — 30" spillway | 7,500 GPH max | 20"L×41"W×14.25"H | two 3" spinweld inlets | max 6,000 gal | black Matala mat + landscape lid + detachable/reversible weir + SS hardware included | side-by-side expandable | Made in USA | Lifetime Warranty. Pond-Less and traditional pond compatible. Questions about waterfall sizing, pump selection, or basin design? Call or text (765) 508-4352 — Mon–Fri, 9 AM–5 PM EST.