2 / 3 stage Whole home Water Filter spanner wrench

## Optimized & Reinforced Wrench for 20" Big Blue Water Filter

This is a complete toolkit for a heavy-duty replacement wrench (spanner) for standard 20" Big Blue whole house water filter systems. It was designed to fit my Toppuror unit, but is compatible with many others using the same housing standard. After the flimsy wrench included with my system broke, I went through a long, collaborative design and testing process to create a tool that is strong, reliable, and optimized for 3D printing.

A quick story and a crucial tip: My first reinforced version, printed in strong PETG, also broke! I thought it was a design flaw, but the real reason was simple user error: I forgot to release the water pressure in the system first! After learning my lesson, even a thin test wrench printed in basic PLA+ was strong enough. This final design is the ultimate version, incorporating numerous strength improvements. The most important tip is to always release the water pressure before attempting to open the housings.

## About the Included Models (Please Read!)

This project includes five different models. It is crucial that you print the "Test Ring" first to ensure the wrench is compatible with your specific filter housing before committing to a full print.

• 03 - Crucial Test Ring (Print This First!) This is a quick, handle-less test print of just the ring and lugs. Print this small part to confirm that the wrench fits your filter housing. It should be a snug fit.
• 01 - The Final Wrench (Recommended) This is the final, fully optimized and reinforced design. It features lugs rotated at a 45-degree angle for the best strength and large, custom-designed fillets to make the handle incredibly strong. This is the recommended version to print after you have confirmed the fit with the test ring.
• 02 - The "Cheater" Wrench (for stubborn housings) This is a specialized version for extremely stubborn or when the canister ends up in an odd position and the original lug positions won't engage. The lugs are slightly offset, which can help engage and "bite" into a housing where a perfectly symmetrical wrench might not fit.
• 04 - The "Speed" Wrench (Thin version if you are brave) A faster-printing version of the final design with a thinner ring wall. It uses less material but is not as strong as the recommended version. Use this if your housings are not excessively tight and you want to save print time.
• 05 - The "Classic" Wrench (No Fillets) This is the strong, optimized design before the large handle fillets were added. It's a simpler design that is still very strong due to the rotated lugs, but it lacks the ultimate reinforcement of the final version.

Note, some offset holes are included in the housing so that yu can use 4mm wide bolts to secure it to a plank to act as a force multiplier for stubborn filter housings. This is completely optional!
 

## Key Dimensions for Compatibility

• Inner Diameter (Ring): 155 mm
• Distance Between Inner Lug Faces: 147 mm
• Number of Lugs/Tabs: 4

## Printing Recommendations

• Recommended Material: I strongly recommend printing in PETG for the best balance of strength and toughness.
• Printing with PLA/PLA+: This also works very well. If you use standard PLA, I recommend printing the full 22mm thickness for safety.
• To Save Print Time: If printing with strong materials like PETG or PLA+, reducing the height to 15mm in the slicer will still produce a very strong part.

## Compatibility

This wrench was designed and tested on a Toppuror water purification products unit using a standard 20" Big Blue housing. This housing is a very common standard, and the wrench is highly likely to be compatible with other brands.

• Big Blue
• Water Tectonics
• Pure Water
• Aqua King
• Flow-Max
• G.A.P. Water Solutions

## Tags / Keywords

• Water Filter
• Wrench
• Spanner
• Big Blue
• 20 Inch
• Whole House Filter
• Borehole
• Replacement Part
• Tool
• PETG
• PLA+
• Takealot
• South Africa
• Filter Housing
• Sump Wrench
• Toppuror
• Bambu Lab A1

## Print Profile

• Nozzle Size: 0.4mm
• Layer Height: 0.2mm
• Wall Loops: 8
• Top/Bottom Shell Layers: 5
• Infill: 100%
• Infill Pattern: Concentric
• Material: PLA+ / PETG
• Supports: None
  
  
  ADDED Parametric version for full customizability