Water Stays Out of Sight
The basin stores recirculating water below the grate so the fountain can appear to rise from decorative pebbles or surrounding hardscape without an open pond.
Fountain Reservoir Basin – 48" Achelous AquaBox®
$749.99
NO Tariffs. Just Savings. PROUDLY MADE IN THE USA!
• Suitable for large fountains
• Overall Dimensions: Round 51.5" diameter X 16" high
• Weight: Approx. 65 lbs
• Grate Dimensions: Round 48" dia. x 2.8"H (in 2 halves)
• Reservoir Capacity: Approx. 95 gallons
• Maximum Static Load: 1,500 lbs
• Includes center support column, pump access covers, and mesh sediment screen
• Lifetime Warranty
Concealed reservoir and structural fountain base
48" Achelous AquaBox®
Create a clean, pond-free fountain installation with a durable polyethylene reservoir built to hide below the finished landscape. Blue Thumb’s patented, U.S.-made 48-inch Achelous AquaBox® combines a 95-gallon water reserve, a two-piece support grate and service access for large recirculating fountain displays.
Before you order: This is the basin assembly, not a complete fountain kit. The fountain piece, pump, tubing and plumbing, decorative stone, electrical service and site-preparation materials are sold separately unless another product listing specifically includes them.
51.5" roundOverall basin diameter
95 gallonsReservoir capacity
1,500 lb.Maximum static load
Approx. 64 lb.Basin, grates and access covers
A Strong Foundation for a Disappearing Fountain
Built for Large Fountain Displays
Four molded supports, a two-piece grate and the included 4-inch rigid PVC center support create a platform rated for a maximum static load of 1,500 pounds.
Service Access Is Built In
Two removable pump-access covers let you reach equipment below the grate without dismantling the entire finished surface.
Is the 48" Achelous the Right Basin?
Plan around the full 51.5-inch outside diameter, not only the 48-inch grate. Basin selection depends on the fountain footprint and weight as well as the expected flow rate and splash pattern. The 1,500-pound static-load rating is an upper limit, not the only sizing factor. Additional center supports may be used for heavier fountains. If any part of the fountain base will not be fully supported, ask Blue Thumb to review the proposed layout before ordering.
What Comes with the AB48AB Basin
Included
Reservoir & Support
- Round polyethylene reservoir basin
- Four molded internal supports
- One 4" rigid PVC center support column
Included
Grate & Access
- Two-piece 48" diameter grate
- Two removable pump-access covers
- Grate designed for planned fountain-plumbing openings
Included
Debris Barrier
A trimmable Altum-Achelous mesh sediment screen helps reduce debris passing through the grate. A replacement screen does not need to be ordered with a new basin.
Plan the Rest of the Fountain System
Required — sold separately
Fountain, Pump & Plumbing
Select a compatible fountain piece, correctly sized pump, tubing and fittings for the fountain height, desired flow and planned layout.
Optional — sold separately
Automatic Water-Level Control
The basin has a spinweld for the 1/2" Fountain Basin Auto Fill Kit. Add the 30 PSI Regulator whenever incoming supply pressure exceeds 30 PSI.
Optional — sold separately
Splash Control & Finish
A 76" square Splash Apron can help return overspray to the basin. The current spec sheet recommends approximately 4–6 bags of polished pebbles, depending on stone size and finish depth.
Specifications & Basin Comparison
The 48-inch model is highlighted. Its inner reservoir below the grate measures approximately 46 inches in diameter by 13 inches high. Use the product-specific page and specification sheet for final planning before purchasing another size.
| Model | Overall dimensions | Grate | Capacity | Max. static load | Approx. weight | Typical scale |
|---|---|---|---|---|---|---|
| 36" Achelous AB36AB |
39.5" dia. × 16" H | 36" dia. × 2.8" H; two halves with two access covers | 60 gal. | 1,000 lb. | 45 lb. | Medium fountains |
| 48" Achelous AB48AB |
51.5" dia. × 16" H | 48" dia. × 2.8" H; two halves with two access covers | 95 gal. | 1,500 lb. | 64 lb. | Large fountains |
| 52" Altum AB52AB |
52.5" × 52.5" × 20" H | 48" × 48" × 2.8" H; two halves with one access cover | 220 gal. | 2,500 lb. | 110 lb. | Large or multiple fountains |
36" Achelous — AB36AB
- 39.5" dia. × 16" H
- 36" grate; two halves and two access covers
- 60 gal.; 1,000 lb. maximum static load
- Approx. 45 lb.; for medium fountains
48" Achelous — AB48AB
- 51.5" dia. × 16" H
- 48" grate; two halves and two access covers
- 95 gal.; 1,500 lb. maximum static load
- Approx. 64 lb.; for large fountains
52" Altum — AB52AB
- 52.5" square × 20" H
- 48" square grate; two halves and one access cover
- 220 gal.; 2,500 lb. maximum static load
- Approx. 110 lb.; for large or multiple fountains
Installation Planning at a Glance
Review the official installation manual before excavation. The sequence below summarizes the Achelous instructions and does not replace the manual or the instructions supplied with the selected fountain and pump.
Choose the Location
Plan the viewing angle and access to a clean fill-water source and nearby electrical service. Locate underground utilities before digging.
Excavate & Prepare
Mark approximately 1–2 inches beyond the basin and excavate about 17 inches straight down. Remove sharp rocks and roots, then level and compact a sand or small-gravel base.
Set Level & Backfill
Support the entire basin base; do not hang it from the rim. Set the top approximately 1 inch below grade, keep it level and compact backfill to prevent movement.
Plan Access & Plumbing
Orient pump access toward electrical service. Drill grate openings only where allowed in the manual, position the screen and tubing, and align the two grate halves over the correct molded supports.
Fill, Test & Finish
Install the selected pump and plumbing, fill with clean water and connect the pump to a nearby GFCI-protected outlet. Test flow and access before adding decorative stone.
Maintain Access
Check water level as evaporation and splash occur, remove accumulated debris, keep the access covers reachable and service the pump according to its instructions.
Important: If using the optional Splash Apron, the manual calls for setting the basin about 1.5 inches below grade and sloping the surrounding area toward the basin. Do not drill above the molded-support locations shown in the manual. Seasonal care depends on the fountain, pump, plumbing and climate; protect those components according to their individual instructions before freezing weather.
Product Resources
Use these documents for final dimensions, site preparation, assembly, optional auto-fill setup and warranty terms.
Optional Auto Fill Installation Video
This official Blue Thumb video covers the separately sold ABDAUTO Fountain Basin Auto Fill Kit. The auto-fill kit and water-supply connection are not included with the AB48AB basin.
“Fountain Basin Auto Fill Kit - 1/2" Step by Step Installation (ABDAUTO)” — video courtesy of Blue Thumb.
Want Help Confirming Basin Fit?
Blue Thumb’s Sales/Tech Team can help review the fountain footprint, weight, flow, pump access, plumbing plan and installation site before you order.
Frequently Asked Questions
Is this a complete fountain kit?
No. AB48AB is the fountain reservoir and support assembly. The fountain piece, pump, tubing, fittings, decorative stone, electrical service and site-preparation materials are sold separately unless a separate kit listing specifically includes them.
What is included with the 48-inch Achelous AquaBox?
It includes the round reservoir basin with four molded supports, a two-piece grate, two pump-access covers, one 4-inch rigid PVC center support and a mesh sediment screen.
How do I know whether this basin will support my fountain?
Confirm the fountain footprint, total static weight, planned placement, water flow and splash pattern. The basin is rated for a maximum static load of 1,500 pounds, but the fountain base must be properly supported and the basin must retain enough recirculating water. Contact Blue Thumb for unusual footprints or heavy installations.
Can the basin be installed above ground?
Blue Thumb’s specification sheet states that AquaBox basins may be installed in ground or above ground depending on the desired fountain elevation. The supplied installation manual details an in-ground installation, so an above-ground structural and finish plan should be reviewed with Blue Thumb before work begins.
How much space and excavation depth should I plan?
The basin measures 51.5 inches in diameter by 16 inches high. The manual calls for marking 1–2 inches beyond the basin and excavating about 17 inches straight down, then setting the level basin top approximately 1 inch below grade. Allow additional working room for utilities, backfill and the final landscape finish.
Are decorative pebbles included?
No. The current AB48AB specification sheet recommends approximately 4–6 bags of polished pebbles to cover the grate. The final amount depends on pebble size, coverage and finish depth. Black and mixed 40-pound bags are available separately.
Is the auto-fill kit included?
No. The basin includes a spinweld connection for the optional 1/2-inch Fountain Basin Auto Fill Kit, sold separately. A 30 PSI regulator is required whenever incoming water pressure exceeds 30 PSI.
How do I access the pump after installation?
The two-piece grate has two removable access covers. Keep at least one access area unobstructed and orient it toward the electrical-service side during installation so routine pump inspection and removal remain practical.
What warranty applies to the basin?
Blue Thumb lists a lifetime warranty for Blue Thumb-branded engineered plastic components, including AquaBox fountain basin reservoirs, for the original purchaser against manufacturing defects. Proper installation is required, modifications void coverage, and compensation excludes associated labor and freight costs. Review the current warranty document for complete terms.
