The white Zeolite pellets in the Biorb filter

The white Zeolite pellets in the Biorb filter

Postby orb-it » Thu Nov 26, 2015 3:22 pm

Over the years members have asked about the white pellets located under the Biorb filter sponge, often asking what they are and the task they perform. Below are a few pointers that will hopefully be useful explaining the basics of what the pellets are and the job they do.

What is Zeolite.
Zeolite is a highly porous and adsorbent mineral tending to be made up of aluminium and silicas, although this can vary depending how and where the zeolite is formed and if the zeolite is natural or artificial. For this reason it is advisable to use a high quality freshwater aquarium specific zeolite, so buying something branded and checking its make up is recommended. Not all zeolite is intended for aquarium use.

What does Zeolite do.
It retains and adsorbs a variety (not all) undesirable materials and holds onto them in a similar way to how a sponge will absorb liquid.
Zeolite does not work forever, in a aquarium that has elevated levels of ammonia the zeolite can become saturated very quickly, in as little as a couple of days, maybe less if levels are extremely high.

Unfortunately there is no way of knowing when the zeolite has become fully exhausted or is about to. If you are relying on zeolite to remove ammonia rather than natural (and free) nitrifying bacteria, the First sign could be you may notice your fish start to look or act differently or you may pick up a ammonia reading when testing the water.

If you had some to hand Zeolite could be beneficial short term in emergency situations where ammonia had become elevated but testing the water and replacing as necessary would be advisable. Although regular back to back (if necessary) 10% dechlorinated water changes would be my personal preferred method of dealing with a emergency where ammonia levels had spiked.

Using Zeolite in the BiOrb filter 24/7.
As mentioned above while it could be a useful chemical if you have some to hand in a emergency should your aquarium have a ammonia spike for any reason it is best not to be used long term.

To maintain a healthy tank you will need adequate nitrifying bacteria colonies present to convert the toxic ammonia created by fish into nitrite then a less harmful nitrate. This happens extremely quickly with adequate bacteria present keeping the fish safe and meeting the demands of your tank. Benefial bacteria will feed off the ammonia present and it will multiply or decrease/die off by feeding off the ammonia present in the tank.

If you are using zeolite all the time in your BiOrb filter you are effectively starving the benefial bacteria by removing its food source. Issue could occur when the zeolite becomes fully exhausted and the adsorption capacity has been met then the ammonia levels will rapidly rise as there is not adequate nitrifying bacteria present to cope with the waste in the tank, in turn subjecting your fish to ammonia and nitrite poisoning.

Under normal circumstances you should not need zeolite. In a properly cycled aquarium that is stocked slowly, sensibly, and adequately maintained, you should not be seeing ammonia or nitrites as the bacteria will convert these very quickly keeping the fish safe. The bacteria are adaptive to the stock in the aquarium so they will grow when needed. However, the zeolite will not be so consistent. There are benefits in keeping the BiOrb as natural as possible. You can not always rely on commercial products to work the way you expect and create a healthy stable aquarium.

Why we do not recommend to have Zeolite in the BiOrb filter while fishless cycling.
As mentioned above Zeolite will remove ammonia, having ammonia in the tank is a essential requirement to successfully fishless cycle the tank. Zeolite pellets should always be removed before starting the cycle.

Where should zeolite be placed in the filter.
Due to its porous nature and being made up a crystal structure consisting of tiny holes of varying sizes, the size of these holes depends on the chemical composition of the mineral. It is often recommended zeolite to be placed in the filter so the water passes through/over the zeolite after the filter sponge, that way the sponge will trap the detritus before it reaches the zeolite. If zeolite becomes covered in detritus, being porous it will loose its ability to do its job effectively.

I have snails in my BiOrb with Zeolite in the filter.

Zeolite can remove/deplete calcium in the aquarium. In harder water particularly there is likely to be more calcium and magnesium present. As the zeolite works by ion exchange if there is more calcium and magnesium present it can absorb those rather than ammonia. It is not recommended to use zeolite long term if you have snails present in your tank as Snail shells require calcium to remain healthy.

Medicating my tank with salt.
Salt should never be used when using zeolite in fresh water aquariums as it can cause the zeolite to release the ammonia it has adsorbed, causing a sudden ammonia spike. Some brands suggest you can use salt to recharge zeolite to enable you to reuse it, but only up to one to two times usually.

This is just a snippet of information available on the biorbforum, for further tips, help and advice please click the register button located above. :D

BiOrb compatible sponges are available here:

10 Filter Pack – UKP £10 (inc. UK P&P)

10 Filter Pack – EURO €18 (inc. Europe EU P&P)

10 Filter Pack – USD $25 (inc. USA & rest of world P&P)

These filter sponges are fully supported on the biorbforum.
:nemo: BARGAIN BiOrb range compatible filter sponge replacements
:nemo: :nemo:
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