fluval c4 vs aquaclear 70

Aquaclear 70 vs Fluval C4 Filter: What’s the Difference?

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When you’re setting up a new aquarium, space is important. You’re going to want plenty of room for your favorite substrate, driftwood, plants, coral, and livestock. Some filters can be bulky and cumbersome in your tank, but if you’re looking to save space in your tank, a clip-on filter is the way to go.

In this article, we’ll be looking at the Fluval C Series C4 Power Filter and the Aquaclear 70 Fish Filter also produced by Fluval. 

Quick Summary

In this article, we will be covering the following:

 Fluval C Series C4 Power FilterAquaClear 70 Fish Filter
Aquarium Capacity40-70 US Gal (151-265 L)30-70 US Gal (151-265 L)
Pump Performance264 US Gal/h (1000 L/h)300 US Gal/h (1136 L/h)
Dimensions of the Filter9 x 6.5 x 8.5″ (22.8 x 16.51 x 21.5 cm)6.2 x 10.7 x 8.6 inches (15.75 x 28 x 21.84 cm)
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Descriptions of Fluval’s C Series C4 Power Filter and the AquaClear 70 Fish Filter

Fluval C Series C4 Power Filter

Both of these filters are clip-on filters, also known as HOB (hang-on-back) filters. HOB filters are preferable for aquarium keepers that don’t have room inside of their tanks for large sponge filtered and don’t have a place to store a canister filter outside of the tank. 

Both filters are suited for freshwater as well as saltwater environments, and they can also be used with proprietary filter media and third party filter media. 

Aquarium Capacity

When choosing a filter, the most important aspect you’ll need to look at is aquarium capacity. The aquarium capacity of a filter is the size of the aquarium that the filter is capable of handling. 

One of the worst mistakes you can make when starting a new aquarium is to choose a filter that has too small of an aquarium capacity. If your tank is too big for your filter, the filter won’t be able to keep the tank clean, and the under-filtered water can harm your fish.

The aquarium capacity of both the Fluval C4 and the AquaClear 70 are nearly same: 30-70 US Gal or (145-265 L) for the AquaClear and 40-70 US Gal (151-265 L) for the C4. Although the C4 is listed at working best for a 40-70 US Gal tank, running it on a lower gallon aquarium is perfectly safe.

It’s recommended to use a filter that has an aquarium capacity slightly higher than your actual tank, especially if you’re overstocked. 

Pump Performance

Aquaclear 70 Fish Filter

The amount of aquarium water that the pump part of the filter can move when it is entirely unfettered by filter media is referred to as pump performance. The output of a pump is measured in gallons per hour (Gal/h) or liters per hour (L/h).

For the most part, you will always have filter media in your filter. They just don’t work correctly without it. Still, knowing the raw power of your filter can give you a good idea of if your filter is strong enough for your tank. 

Although the aquarium capacity of the C4 and the AquaClear 70 filters are almost identical, there’s quite a gap between the pump performance, with the AquaClear 70 coming out on top.

  • Pump performance of the Fluval C Series C4: 264 US Gal/h (1000 L/h)
  • Pump performance of the Aquaclear 70: 300 US Gal/h (1450 L/h)

Dimensions of the Filters

When choosing a filter for your aquarium, you also need to ensure you have a product that will properly with within your tank. Here are the dimensions for the two filters currently being compared:

  • Fluval C Series C4 Dimensions: 9” x 6.5” x 8.5″ (22.8 x 16.51 x 21.5 cm)
  • AquaClear 70 Dimensions: 6.2” x 10.7” x 8.6” (15.75 x 28 x 21.84 cm)

Although these two filters may seem large compared to the size of your tank, both filters are clipped onto the rim of your tank, and only a small portion of them are actually inside. HOB filters don’t have the filter power of canister filters, but they can still work well as long as you pay attention to the listed aquarium capacities. 

Pros and Cons of Fluval’s C Series C4 Power Filter and the AquaClear 70 Fish Filter

These filters are very similar, but there are still a few key differences.

Pros and Cons of the Fluval C Series C4

Here are some of the benefits as well as fallbacks of the Fluval C Series C4 filter.


  • Made by a trusted manufacturer: Fluval 
  • 5-stage filtration
  • Modular media compartments so that your filter media can be swapped out easily


  • Lower pump performance than the AquaClear 70
  • Larger than the AquaClear 70 filter
  • Filter media needs to be changed out more quickly compared to other filters

Pros and Cons of the AquaClear 70 

Here are some of the benefits and problems with the AquaClear 70 filter.


  • Extremely quiet
  • Smaller size than the Fluval C Series C4 filter
  • Large capacity for filter media


  • It can rattle enclosure lids
  • Lower flow rate than the Fluval C4

Final Thoughts

Both filters are highly rated HOB filters that are suitable for aquariums up to 70 gallons. Either filter is a superb choice for both amateur and experienced aquarium keepers, and they both will keep your tank water crystal clear. 

These are very comparable filters besides their size differences and pump performances. Consider your available space and what kind of filter media you prefer, and—as long as you have an aquarium under 70 US Gal—either of these great filters should suffice for your tank.

See Also:
How Long Does a Fish Tank Filter Last?
Can You Clean the Fish Tank Filter Cartridge?
How Long Do You Leave the Filter on in a Fish Tank?
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