Waterpik
Waterpik Aquarius WP-660
$99.99
2 sellers$99.99read
Released 2013
Best Water Flossers · head-to-head
Waterpik Aquarius WP-660 vs h2ofloss HF-9
A sourced, side-by-side comparison. h2ofloss HF-9 is cheaper at $43.90. Every spec and price links to its source.
h2ofloss
h2ofloss HF-9
$43.90Cheaper
Which is better: the Waterpik Aquarius WP-660 or h2ofloss HF-9?
On the specs we track, they're closely matched. The h2ofloss HF-9 is the cheaper at $43.90.
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Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec |  Waterpik Aquarius WP-660 |  h2ofloss HF-9 |
|---|---|---|
| US price | $99.99 | $43.90 |
| Brand | Waterpik | h2ofloss |
| Released | 2013 | — |
| Type | countertop | countertop |
| Tank capacity (ml) | 651 | 800 |
| Pressure settings | 10 | 5 |
| Max pressure (psi) | 100 | 110 |
| Tips included | 7 | 13 |
| Power | corded | corded |
| Runtime (min) | 1.5 | — |
| Release | 2013 | — |
Sources — Waterpik Aquarius WP-660: waterpik.com (verified 2026-11-05). h2ofloss HF-9: h2ofloss.com (verified 2026-11-05).
What's the difference between the Waterpik Aquarius WP-660 and h2ofloss HF-9?
Where the two actually differ on the specs we track (4 of 7). Matching specs are omitted.
- Tank capacity (ml): Waterpik Aquarius WP-660 651 vs h2ofloss HF-9 800
- Pressure settings: Waterpik Aquarius WP-660 10 vs h2ofloss HF-9 5
- Max pressure (psi): Waterpik Aquarius WP-660 100 vs h2ofloss HF-9 110
- Tips included: Waterpik Aquarius WP-660 7 vs h2ofloss HF-9 13