Alumina air stones for garden ponds, koi ponds, and water gardens are much stronger than silica air stones. Each Alumina pond air stone is self weighted and has a threaded fitting embedded into the air stone which is much stonger and less likely to break.
Two sizes to choose from:
| Alumina Pond Air Stone | Dimensions | Fitting Size | Price |
| 6" | 1.5" x 6" Long | 1/2" Male Pipe Thread | $29.99 |
| 9" | 1.5" x 9" Long | 1/2" Male Pipe Thread | $29.99 |
