Real owners lean toward the Eheim Classic 2217: 82% of 80 owners recommend it, vs 45% of 22 for the AquaClear 70 Power Filter.
Verdicts aggregated from Reddit, enthusiast forums, and YouTube owner comments — affiliate reviews excluded. Sample sizes differ; judge accordingly. How we score
Owners of both filters describe long-lasting, reliable filtration and clear water, with each base reporting units that run for years or decades and praising their value. The Eheim Classic 2217's fans treat it as a buy-it-once, near-silent canister with excellent biological filtration and no fragile electronics that backwashes easily into a bucket, though many note the media sits loose rather than in lift-out baskets and that its flow can leave dead spots, prompting some to add a powerhead. The AquaClear 70's owners widely call it the best hang-on-back filter, prizing a customizable media chamber that works like a canister for less money, but some find it finicky to restart after a power outage or once the impeller gets dirty, and its strong outflow often needs configuring to tame, with a few removing it from planted tanks to stop it uprooting plants. Buyers wanting a silent, no-frills canister for a roughly 75-gallon or planted tank and decades of reliability gravitate toward the Eheim. Those wanting a flexible, canister-like hang-on-back filter for planted or refugium setups lean toward the AquaClear. Neither is simply better; the choice hinges on canister-versus-HOB form factor and whether the concern is too-gentle flow with dead spots or an outflow strong enough to need taming.
“loving the canister. very quiet”— @T_Quik on YouTube
“If I had to choose again I'd probably buy two Eheim. Though the Fluval is a bit easier to maintain and it does suck up fish waste better, the noisy impeller and crappy build quality of it has kind of turned me off it.”— Mun-Mun on Reddit
“My life would be easier and my tanks would look better if I had only bought Fluvals!”— @shavinmccrotch9435 on YouTube
Owners of both filters describe long-lasting, reliable filtration and clear water, with each base reporting units that run for years or decades and praising their value. The Eheim Classic 2217's fans treat it as a buy-it-once, near-silent canister with excellent biological filtration and no fragile electronics that backwashes easily into a bucket, though many note the media sits loose rather than in lift-out baskets and that its flow can leave dead spots, prompting some to add a powerhead. The AquaClear 70's owners widely call it the best hang-on-back filter, prizing a customizable media chamber that works like a canister for less money, but some find it finicky to restart after a power outage or once the impeller gets dirty, and its strong outflow often needs configuring to tame, with a few removing it from planted tanks to stop it uprooting plants. Buyers wanting a silent, no-frills canister for a roughly 75-gallon or planted tank and decades of reliability gravitate toward the Eheim. Those wanting a flexible, canister-like hang-on-back filter for planted or refugium setups lean toward the AquaClear. Neither is simply better; the choice hinges on canister-versus-HOB form factor and whether the concern is too-gentle flow with dead spots or an outflow strong enough to need taming.
Owners point the Eheim Classic 2217 at owners of roughly 75-gallon tanks, and planted-tank keepers wanting strong biological filtration.
Owners point the AquaClear 70 Power Filter at owners who want a customizable media chamber, similar to a canister filter but cheaper, and planted or reef HOB setups running refugium media like chaeto, floss, and purigen.
The most-cited downside of the Eheim Classic 2217 is media isn't in easy lift-out baskets. For the AquaClear 70 Power Filter, it's can be finicky to restart after a power outage or once the impeller gets dirty, sometimes needing repriming or grinding/failing to cycle water at all.