What Is the Filter Floss Used for Stopping Microbubbles in Aquariums?

Bubbles can block water lines.
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Like many high-tech devices, many types of advanced aquarium equipment can fail due to little problems -- extremely little one. Microbubbles can foul an expensive and complicated device like a sump filter. Filter floss can help mitigate this problem but has drawbacks other solutions don't have.


Microbubbles are just very small, sometimes microscopic, air bubbles. Large masses of tiny microbubbles can make water look cloudy -- like hot tap water. Many types of aquarium equipment can generate microbubbles, including protein skimmers and power heads. Microbubbles can collect in aquarium plumbing and, over time, build up into air pockets. If enough air gets into the aquarium plumbing, it can block pipes and break siphons. If the siphon happens to be on the return drain to an aquarium, this can result in a flooded home. Aquarium hobbyists use several methods to reduce microbubbles, including filter floss and baffles.

Filter Floss

Filter floss consists of coarse sheets of an artificial fibrous material. It has many uses in aquariums. For one, it can provide mechanical filtration -- the material makes a great strainer to remove debris from aquariums. It also has a high surface area-to-volume ratio, making it useful for biological filtration. Since it costs relatively little, aquarium hobbyists have found even more uses for the material, including blocking microbubbles.

Problems With Floss

Sometimes, filter floss can work too well. The fibers can collect enough physical debris in them to clog. When this happens, the filter floss can cause many of the problems it is supposed to prevent. For example, if you have a screen of filter floss to protect an overflow box and it clogs, the aquarium will overflow just as dramatically as it would have if microbubbles broke the siphon. You can mitigate this by regularly checking and cleaning your filter floss, but experts recommend using other tools to block microbubbles due to the risk of clogs.


Many many hobbyists make their own sump filters and overflow boxes. With a DIY approach, you can design your sump to reduce microbubbles without filter floss. Sumps -- and sometimes overflow boxes -- usually feature series of baffles. Baffles create a sort of a maze for bubbles, diverting them away from sensitive equipment and breaking some. Baffles are usually large enough to resist blockage much better than filter floss. However, baffles may take more room and require you to design them into the sump itself.

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