Pros and cons of zeolite

Zeolite is a natural silicate rock. It has a large reactive surface area that acts like an ion exchanger. Pollutants dissolved in the water are thus deposited on the zeolite.

Zeolite primarily absorbs ammonium. This prevents the increase in the amount of nitrate. Because some zeolites are quite porous, they are also suitable as biological filter material.

Because zeolite is a natural material, there are different qualities of zeolite. The ability to exchange ions is therefore not the same for every zeolite and the same ions are not always exchanged.

Very good zeolite types come from Australia. Less good varieties come from Russia. The Russian varieties are very solid and therefore not suitable as biological filter material.

However, the precise effects of the commercially available zeolites are not described in detail on the packages. If you have examined a product and found it to be useful, you may not get it back.

Zeolite is definitely not a miracle cure. Algae problems are z. B. only eliminated in the long run if good growth conditions for the aquatic plants are present.

Zeolites can be used to soften water, buffer ammonium and thus make nitrification more even.
However, zeolite not only absorbs unwanted substances from the aquarium water, but also useful substances such as iron and trace elements that are required for good plant growth.

Sorbents such as activated carbon, alumina and zeolites can help limit the amount of unwanted substances in special situations, but should not be used continuously. A large amount of mulm (water humus) also acts as a sorbent, but also has other positive properties.

There are reports that the algae disappeared first, but then the plants died as well. On the other hand, there are reports of magnificent plant growth when using zeolite. Because zeolite is a natural ion exchanger, it absorbs ammonium for a while. This reduces the growth of algae in heavily loaded aquariums. In an unpolluted aquarium, however, the plants need some ammonium. Zeolite then leads to stunted growth. If the zeolite is largely loaded with ammonium after a few weeks, it filters biologically like any good filter material. In order to regenerate zeolite, it is placed in a 1%, iodine-free salt solution for around 24 hours.

How good the biological filter performance is depends on the type of zeolite. If the pores are too small, too few bacteria settle. Exactly the same if the zeolite contains hardly any pores.

When used as a filter medium, zeolite quickly grows biologically and is then only populated on the surface, nothing more.

Some zeolites appear to dissolve in water into a mushy substance. As a result, the entire filter can become dirty if the zeolite is not cleanly covered at the top and bottom, e.g. B. with filter floss.