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How Can You Lower the Bioload in Your Aquarium?

Reducing Bioload in Fish Aquariums San Diego, CA

One of the most appealing aspects of the fish keeping hobby is that aquarists get to learn practical lessons in biochemistry and microbiology. Without understanding the biological and environmental factors that can contribute to a healthy tank, aquarists wouldn’t be able to adequately maintain a self-enclosed aquatic ecosystem. One important lesson to learn is related to the biological load of a tank, more commonly referred to as “bioload.” Even though bioload sounds like something you could measure, there really aren’t any standard unit measurements, but you should always try to keep it as low as possible.

Understanding Bioload

When you see recommendations about stocking a saltwater or freshwater aquarium with fish and other aquatic creatures, some bioload considerations are included in the estimation. You can search online and find various fish stocking calculators that take into consideration the size and shape of the tank along with the species you want to keep. Most of the time, the recommendation will be more or less equivalent to “one inch per gallon of water,” but there’s more than just swimming space taken into account with this estimation. There’s also the matter of how much waste various species can produce.

Species that Produce a Larger Bioload

All aquarium species, even plants, will add to the bioload, which consists of the chemicals produced by breathing, excrement, plant decay, pieces of dead scales, and uneaten food. The characteristics of the species determine their contribution to the bioload. For example, non-fancy goldfish are known to be messy eaters with active digestive systems. Ghost shrimp, on the other hand, are scavengers that will feed on some of the bioload without producing much of it. Aquatic plants such as hornwort, which can shed numerous needles when they’re moved, also add more to the bioload compared to other plants such as cabomba or Christmas moss.

The Problem with High Bioload Levels

It’s in the best interest of aquarists to keep the bioload as low as possible. This goes for those who keep both smaller aquariums or larger tanks that can hold water volumes greater than 100 gallons. A high bioload will break down into nitrates, nitrites, and eventually ammonia, which is toxic for all aquatic species. Furthermore, higher nitrogen levels will promote algae bloom since the beneficial nitrobacter colonies won’t be able to keep up with all the nitrates and nitrites. To accommodate a larger bioload, you can always increase the filtration size with a canister filter:


There’s no such thing as too much surface area in filtration.

Keeping the Bioload to Low Levels

The rule of thumb is to keep fewer and smaller species in larger tanks. If you have a 10-gallon tank with seven fish, you should either get a 20-gallon tank or donate three of your fish to another aquarist. Regular water changes will go a long way toward keeping the bioload in check. Other recommendations include introducing scavengers such as ghost shrimp. Finally, if water test strips show ammonia levels rising even though you know the tank has completed the nitrogen cycle, this could mean you need to upgrade the filtration system.

To keep the bioload in your tank in check, make sure you get everything you need from Aquatic Warehouse, a leading provider of freshwater and saltwater aquarium supplies. Stop by our store in Kearny Mesa, order from us online, or give us a call today at 858-467-9297 if you have any questions.


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    San Diego, CA 92123
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