Blue Thumb PB1854 Small 20" Cascading Waterfall Kit – Complete Pondless Backyard DIY Water Feature System

The PB1854 is a complete DIY pondless waterfall system. It includes:

• 20" DIY Cascade Box (cascade waterfall spillway)
• Canyon Matrix™ — all-in-one pump housing and 21-gallon water reservoir (26.5"L × 16"W × 11.5"H; Lifetime Warranty)
• Mag-Drive pump (~1,495 GPH submersible)
• Pump Discharge Assembly with Check Valve
• PondGard Rubber Liner — 45-mil EPDM, 6'×10'
• Protective Underliner
• Black PVC Flex Pipe — 1" × 7'
• 8 oz Pond Cleaner & Muck Buster
• Color Instructions (illustrated installation guide)

Not included: Decorative rock, river stone, and gravel must be sourced separately. These materials are used to cover the basin, stream bed, and Canyon Matrix™ to create the natural-looking waterfall appearance.

A pondless waterfall circulates water entirely through a hidden underground reservoir — there is no visible open pond. Here’s how the PB1854 system operates:

• The Canyon Matrix™ is buried in an excavated basin at the base of the waterfall. It holds 21 gallons of water and houses the pump, completely hidden below the surface.
• The Mag-Drive pump inside the Canyon Matrix™ draws water up through the 1" Black PVC Flex Pipe to the 20" DIY Cascade Box at the top of the feature.
• Water overflows the cascade box as a smooth sheet, flows down a rocky stream bed (up to 7\' long), and disappears back into the gravel-covered basin to recirculate.

From the surface, the feature looks like a natural spring emerging from rocks — water appears, flows, and disappears. No visible basin or pond is needed.

The 20" DIY Cascade Box creates a smooth, even water sheet across its full 20" width. Its design allows rocks to be stacked around and above the box to make it look like a natural rocky ledge from which water emerges. The box is sized for a Mag-Drive pump up to 2,500 GPH maximum flow, giving room to upgrade the pump in the future if desired.

Note: The PB1854 uses the standard DIY Cascade Box. Blue Thumb’s Elite kits use the Elite Cascade Spillway Box, which features internal baffles and is engineered for heavier rock stacking and higher flow rates. The DIY box is ideal for the PB1854’s entry-level ~1,495 GPH pump and 7' maximum stream.

Yes — pondless waterfalls are the safest water feature option for households with children and pets. The Canyon Matrix™ reservoir is fully buried underground, covered with rock and gravel. There is no open pool of standing water at any accessible depth. Children and pets can safely interact with the water flowing through the rocky stream without risk of submersion.

The shallow, fast-moving water in the stream bed is not deep enough to pose a drowning hazard, and the system can be turned off simply by unplugging the pump whenever desired.

Maintenance is minimal by design:

• Water top-off: Evaporation will gradually lower the water level in the Canyon Matrix™. Periodically check the level through the access lid and top off with a garden hose as needed. Frequency depends on climate and season.
• Leaf and debris removal: In fall, clear autumn leaves from the surface rock/gravel to prevent them from washing into the basin and clogging the pump. Use the included Muck Buster tablets periodically to control organic buildup.
• Pump cleaning: Remove the pump from the Canyon Matrix™ periodically and rinse the intake screen to remove accumulated debris.

Because the Canyon Matrix™ reservoir is shaded underground, algae growth is dramatically reduced compared to open-pond systems. Cleaning frequency is typically seasonal rather than weekly.

The PB1854 kit provides materials to build a stream up to 7 feet long with up to 2 feet of elevation change from the base of the Canyon Matrix™ to the top of the 20" Cascade Box. The kit is ideal for small-to-medium landscape spaces, corners, and patio features where a compact, impactful water feature is desired.

The 7' maximum is determined by the included 7\' of Black PVC Flex Pipe and the Mag-Drive pump’s flow capacity at height. If you need a longer stream, additional pipe can be purchased separately, but the pump’s GPH at increased head height must be accounted for in planning.

The Canyon Matrix™ is Blue Thumb’s all-in-one pump housing and water reservoir unit designed for smaller DIY pondless installations. Key specs:

• Dimensions: 26.5"L × 16"W × 11.5"H (13"H with access lid)
• Water capacity: 21 gallons
• Maximum pump flow: 2,500 GPH
• One-piece molded construction with access lid (11.25" diameter access hole)
• UniSeal for 1.5" flex hose passthrough to pump
• Auto Fill spinweld for optional auto-fill kit (PB1342, sold separately)
• Lifetime Warranty; Proudly Made in USA

Blue Thumb’s Elite kits use a separate Elite Pump Canyon (pump vault only) plus separate Basin Matrix blocks (water storage). The Canyon Matrix™ combines both functions into a single unit — simpler to install and ideal for the PB1854’s smaller footprint. For larger installations requiring more water volume or a bigger pump, the separate Elite Pump Canyon + Matrix block system provides more scalability.

In climates where temperatures drop below freezing, proper winterization protects the pump and Canyon Matrix™:

• Pump: Remove the Mag-Drive pump from the Canyon Matrix™ before the first hard freeze. Store it submerged in a bucket of water in a frost-free location (garage or basement). Letting a pump freeze dry can damage the seals and impeller.
• Canyon Matrix™: Completely drain the Canyon Matrix™ reservoir to prevent ice expansion damage. The lid provides easy access for this. The Canyon Matrix™ itself is built to remain in the ground through winter.
• Liner: The PondGard 45-mil EPDM liner is frost-resistant and can remain in place year-round.
• Spring start-up: Reinstall the pump, refill the system, and add a dose of Muck Buster to refresh the water before restarting.

Yes. Several upgrade paths are available:

• Longer stream: Purchase additional Black PVC Flex Pipe to extend the stream run. Be aware that a longer run or greater elevation will reduce the pump’s effective GPH; verify the pump’s flow curve at the increased head height.
• Auto Fill: Add the Blue Thumb Auto Fill Kit (PB1342, sold separately) to the Canyon Matrix™’s Auto Fill spinweld. This connects to a garden hose supply and automatically maintains the water level, eliminating manual top-offs.
• Pump upgrade: The Canyon Matrix™ accepts pumps up to 2,500 GPH maximum flow. A higher-GPH pump can increase the water sheet volume and visual impact of the 20" cascade box.
• Lighting: Blue Thumb offers compatible underwater and landscape lighting for nighttime illumination of the waterfall and stream.

The PB1854 is Blue Thumb’s DIY entry-level 20" kit, while the Elite series are the premium pondless waterfall kits with higher-capacity components:

• PB1854 (this kit, DIY): 20" DIY Cascade Box, Canyon Matrix™ (all-in-one basin), ~1,495 GPH Mag-Drive pump, 1"×7\' pipe, up to 7\' stream. Best for compact spaces, first-time DIY builders, and budget-conscious installations.
• PB16KIT (Elite Small, 16"): 16" Elite Cascade Spillway Box, Elite Pump Canyon (separate vault) + Basin Matrix blocks, IllumiFlow 2,100 GPH pump, 2"×25\' pipe, up to 6\' stream. Higher flow, premium spillway construction.
• PBE40CFK (Elite XL, 40"): 40" Elite Cascade Spillway Box, large Elite Pump Canyon + 8 Matrix blocks, IllumiFlow 7,800 GPH pump, 3"×25\' pipe, up to 18\' stream. For large landscape focal points.

The key trade-off: the PB1854’s Canyon Matrix™ is simpler to install than the Elite kit’s separate Pump Canyon + Basin Matrix configuration, but provides less water volume and lower flow capacity for larger features.