We recommend performing partial water changes every week. When keeping aquariums with high stocking densities or with more delicate / demanding species, more frequent water changes are required. Always make sure the replacement water is of the right temperature and conditioned with Fluval Aqua Plus Water Conditioner.

Does gravel cleaning remove beneficial bacteria?

It does not. Though much of your cycle is indeed in the gravel bed, cleaning detritus from the gravel will not harm these bacteria. It does however reduce the level of bad bacteria that can be harmful to your fish as these thrive in unsanitary conditions.

Can this Fluval FX gravel cleaner be used in a marine aquarium?

Yes, the Fluval FX gravel cleaner can be used in salt water, provided that there is an FX filter to pair it with.

Can the FX gravel cleaner be used on sand?

Yes. There is a flow control valve that allows you to slow down the strength of the suction. This will in turn reduce the amount of sand you could potential suck up. Always remember that sand cleaning is different and you shouldn’t insert the cleaner into the sand, but rather just hover above it to lift the detritus.

Do I need to perform water changes if I vacuum the gravel?

Absolutely. Water changes are essential for maintaining a healthy aquarium. Whilst gravel cleaning helps remove accumulated waste, it cannot replace the many benefits of regular water changes.

All living organisms within an aquarium use essential minerals simply to survive. Fish, invertebrates, aquatic plants and even the beneficial bacteria that power the nitrogen cycle require elements such as calcium, magnesium and trace minerals. Over time, these minerals become depleted and must be replenished through water changes.

At the same time, nutrients derived from waste, including nitrogen and phosphorus compounds, gradually build up within the aquarium. If left unchecked, these can negatively impact water quality, livestock health and the overall appearance of the aquarium.

Fish also release hormones, pheromones and other dissolved organic compounds into the water. In nature these substances are constantly diluted by the vast volume of water available, but in an aquarium they can accumulate over time. Whilst these chemical signals play an important role in fish behaviour and communication, excessive build-up may contribute to reduced growth rates, suppressed breeding behaviour and a general decline in aquarium conditions. Regular water changes help dilute these compounds and maintain a healthier environment for your livestock.

Without regular water changes, important water parameters such as pH, GH and KH will often decline over time. In extreme cases, this can lead to a condition known as Old Tank Syndrome, where the water becomes increasingly acidic and unstable. Correcting Old Tank Syndrome can be challenging, as large corrective water changes may cause sudden shifts in water chemistry that place additional stress on fish and other aquarium inhabitants.

For these reasons, gravel vacuuming should be viewed as a valuable part of aquarium maintenance, but not a replacement for regular water changes. Both work together to maintain excellent water quality and provide the best possible environment for fish, plants and beneficial bacteria.