Catit Water Fountain Pre-Filter — HAI BAO Pump

An oversized pre-filter designed to mount around the factory filter of the HAI BAO HB-200 pump used in Catit cat water fountains (including the popular Flower Fountain and similar models). The stock filter clogs quickly with cat hair, which reduces flow and forces frequent cleaning — this larger mesh cage catches hair before it reaches the factory filter and impeller, keeping water flowing longer between cleanings.

How it works The print fits around the pump's existing factory filter, acting as a first line of defense. Hair and larger debris get trapped on the outer mesh, while the original filter continues to handle finer particles. Result: less impeller jamming, better long-term flow, and longer intervals between deep cleans.

Recommended print settings

• Nozzle: 0.6 mm (profile is set up for this — a 0.4 mm nozzle also works well)
• Material: PETG (Sunlu PETG Black used in mine — food/water-adjacent safe enough for this use, and more durable than PLA in standing water)
• Support material: dedicated PLA support interface recommended (I used Bambu Lab Support for PLA — generic PLA as a support interface also works fine)
• No supports needed beyond the dedicated interface

Tuning the fit Tolerances vary significantly between printers and filament batches. I strongly recommend doing a few test prints, scaling in ±0.25% steps, until the part fits snugly around your factory filter without being too tight to remove for cleaning.

Customizing the mesh You can experiment with infill density and infill pattern under the Objects tab in your slicer to change the mesh structure of the filter cage. Gyroid and cross-hatch infills give the best results in my testing — they create a 3D mesh that catches hair effectively without choking flow. Lower densities (15–25%) keep flow high; higher densities catch more debris but need cleaning more often.

Maintenance Rinse under running water during your normal fountain cleaning cycle. The larger surface area means cleaning is faster and easier than picking hair off the small factory filter.