Using various ceramic filter media is a highly effective way to keep biological balance and manage the nitrogen cycle in aquariums. Due to their porous structure, ceramic or quartz filter media are an excellent substrate to accommodate nitrifying bacteria, which play an essential role in the aquarium nitrogen cycle.

These nitrifying bacteria convert the ammonia generated by the decay of leftover food, fish feces, and other organic material into nitrite and then into nitrate. Not only are nitrates far less toxic for fish, but they are also consumed by aquatic plants and seaweed and are easily removed when changing water.

However, it is hard to assess the performance of certain filter media, especially when producers use various tricks to make some filter media more appealing.

For example, how would one evaluate which filter medium in the photo below is better?

Intuitively, the buyer sees the pores in the sample on the left and opts for this medium. However, the sample on the right may have much better porosity; the pores may be so tiny that they are invisible to the naked eye but are just the right size for bacteria.

Therefore, I have decided to introduce a number of criteria to empirically assess bioceramics quality in order to evaluate whether a particular filter medium is suitable for aquarium use.

Porosity

Porosity is one of the key parameters for your bioceramics performance assessment. It includes several characteristics.

Pore size and absorption rate

On the one hand, the smaller the pores are, the higher their quantity is in the filter medium, and the larger the area for bacteria accommodation. Normally, pores are not visible to the naked eye. How can you determine whether your medium is porous or not? Simply take a dry ceramic medium and add a few drops of water—or, better yet, colored water. A surface with fine pores will absorb the water within a second. If the pores are larger, the water will be absorbed instantaneously.

While fine pores provide much more surface for bacteria accommodation, the longer time required for water penetration may prevent bacteria from receiving enough essential nutrients and oxygen. In this case, the whole area will not be used anyway. Additionally, when a filter is working, it is mechanically clogged with particles, and fine pores will get blocked much faster than bigger ones, thus lowering filtration efficiency.

Findings:

1. Pores are invisible or nearly invisible to the naked eye.
2. The drop method should show instantaneous water absorption.

 Pore structure

Importantly, pores inside the ceramic media must be interconnected, thus creating a whole system. This system may be observed during a drop test: when you place several drops of colored water on the ceramic medium, you will see the water distributing throughout the ceramic rather than staying only at the spot of the actual drop.

Moisture absorption volume

During the drop test, provided all the samples have approximately similar volume, it is possible to find the volume of water absorbed by the ceramic medium: the more water is retained in the medium, the more pores there are.

Material inertia

Material inertia is a vital indicator of how your bioceramics can impact water parameters in the aquarium. To optimize production costs, some manufacturers use chemical ingredients that remain in the ceramics and dissolve in water, changing their parameters. A simple test will allow you to identify whether your bioceramics are inert.

First, rinse the samples in osmosis water, since otherwise they might contain dust particles that would affect the result. Make sure to measure osmosis solid dispersion and pH parameters before the test. Measure 50 ml of osmosis water and add some to the samples under study (2-3 samples are enough). 

Leave the samples for 24 hours, and then measure solid dispersion and рН.

1. It is normal for the samples to raise solid dispersion in water. However, we shouldn't expect it to increase by thousands of percent. For example, if the initial solid dispersion was 10ppm, then going to 20 or 30 is quite good. However, if it surges to 100 or higher, that's a bad sign.
2. рН is another key parameter in this test. The measured рН must stay within the range of 7.0-7.2. As a rule, if the solid dispersion does not change dramatically, рН is nothing to worry about. And vice versa: if solid dispersion soars to 100ppm or more, the рН value will change significantly.

When choosing ceramics for an aquarium, it is preferable not to use ceramics that considerably change water parameters in the material inertia test.

We used all these principles when selecting bioceramics for our farm, and all these ceramics media are available in our online store.

While testing various ceramics filter media, we came to the conclusion that it is optimal to use a mix of several types of ceramics. A variety of pore sizes provides the best conditions to accommodate nitrifying bacteria. We have not done deeper research, but we attribute this to the fact that there is a variety of nitrifying bacteria, and different bacteria prefer different sizes of pores. Thus, the best performance results from a combination of several types of ceramics, all of which you can buy on our website.