AquaClear 70 vs Seachem Tidal 55
The two best refillable-basket hang-on-backs for a mid-size tank. The AquaClear 70 is the high-flow value pick; the Seachem Tidal 55 adds a self-priming pump and a surface skimmer. Here's which HOB suits your tank.
The quick verdict
Both ditch disposable cartridges for a big open basket you pack yourself, so both filter better than a basic HOB. If you want more flow for a slightly bigger tank at a lower price, the AquaClear 70 is the value champion. If you want a self-priming pump and a surface skimmer for a clean, glass-clear water surface, the Seachem Tidal 55 is worth the premium.
| AquaClear 70 | Seachem Tidal 55 | |
|---|---|---|
| Flow rate | 1136 L/h (adjustable) | 900 L/h (adjustable) |
| Rated tank size | 152–265 L | Up to 200 L |
| Media | Large refillable basket | Large open basket |
| Surface skimmer | No | Yes, built-in adjustable |
| Priming | Manual | Self-priming Sicce pump |
| Extras | Flow control | Flow dial + maintenance reminder |
| Value | ≈ $75 | ≈ $90 |
Flow and value vs skimmer and convenience
The AquaClear 70 gives you the most flow for the money. Its extra-large refillable basket runs any mix of foam, carbon and BioMax, its unusual re-filtration path holds water against the media longer than a cartridge HOB, and it comfortably clears 4× turnover on a 265 L tank. The Seachem Tidal 55 matches the open-basket flexibility and adds two things the AquaClear lacks: a self-priming Sicce pump that starts itself, and a built-in surface skimmer that clears the oily film for better gas exchange and a cleaner-looking surface. On a planted tank without much surface agitation, that skimmer is a genuine advantage.
Which should you buy?
Our pick
For a straightforward 150–265 L community tank where flow and value lead, take the AquaClear 70. For a planted or lightly-aerated tank where a clean surface and no-fuss priming matter — or a tank up to 200 L — the Seachem Tidal 55 is worth the extra. Read the full AquaClear 70 review and Seachem Tidal 55 review, or see all aquarium filters.
Frequently asked questions
AquaClear 70 or Seachem Tidal 55 — which is better?
Both are excellent refillable-basket hang-on-backs. The AquaClear 70 pushes more flow (1136 L/h vs 900 L/h) and suits slightly bigger tanks up to 265 L, at a lower price. The Seachem Tidal 55 adds a self-priming pump and a built-in surface skimmer that clears the oily film off the water. Pick the AquaClear for flow and value; pick the Tidal for the skimmer and hands-off priming.
What does the Seachem Tidal’s surface skimmer actually do?
It draws water from the very top of the tank as well as lower down, pulling in the oily protein film that builds on a still surface. That improves gas exchange and keeps the water clear viewed from above — genuinely useful on a planted or lightly-aerated tank. The AquaClear 70 has no skimmer, so on a still-surface planted tank the Tidal has a real edge.
Which hang-on-back is easier to set up and service?
The Tidal 55 self-primes — you fill the tank, plug it in, and it starts itself — and it has a maintenance-reminder dial. The AquaClear 70 is dead simple too and cheaper to run, but you prime it and it has no skimmer to tune. Both use an open, refillable basket so you clean one stage at a time and keep your bacteria alive.
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