Is zeolite useful as aquaponics media?

[Louise]

Someone has been trying to sell me zeolite for use in green roofs, and I was curious whether it might be useful in aquaponics. Here's a pdf with information on the specifications. Seems a bit too high pH, to me, and I'm also wondering about it's ability to bind all sorts of elements. The salesperson said the plants can easily extract what they want from the zeolite.

Zeolite%20info%20SI-B.pdf

What do you think?

[TCLynx]

I know zeolite is often used for aquarium filters but I don't know if it would be worth while to use for aquaponics.  Seems to me the cost would be high for questionable benefit.  We don't necessarily want the ammonia absorbed, we want it converted by the bio-filter bacteria into nitrite and then nitrate which we want free flowing in the water for the plants to take it up where ever they are in the system.

And yes, if the stuff keep the pH between 7-8 then it would be higher than we really like for aquaponics.

However it may be handy stuff for a filter if you have a fish tank without enough space to make it a whole aquaponics system and it is under filtered.  I don't know if you have to replace it regularly though.

[Vlad Jovanovic]

I've become a big, big fan of zeolite after doing some side by side potted plant "tests", and in a little corner of the garden. So much so, that I'm trying to source about one ton of the stuff (if I can get a reasonable price).

I can see it having an application in certain aquarium settings, but in aquaponics...I have to agree with TC, and have come to a similar conclusion. I don't really think we'd want anything sequestering, or binding up nitrogen in a normal AP setting IMO.

[RupertofOZ]

One of the problems with using zeolite in aquaponics, is that while it "binds" ammonia... it also releases it... if you salt your system....

 

i.e.... if you're treating your fish for disease....

 

The last thing you need when your fish are diseased/under stress.... is a sudden ammonia spike.....

 

As it "binds" ammonia.... it also therefore deprives your system of a level of nitrification... and benefits for plant growth.... (to some extent)...

 

It might have some application in temporary, or cycling stages... but IMO there are better mediums to use as grow bed media...

[Japan Aquaponics - アクアポニックス 日本]

Zeolite is also used to attract radiation (for example they are throwing it into the ocean outside the Fukushima nuclear plant) and so it was suggested to me (maybe even by Rupert?) that zeolite could be used in aquaponics systems in Japan.

I did a bit more research about zeolite in light of this, and another difficulty is that there seems to be a number of sources of zeolite and that medium from these different sources could have profoundly different effects on the chemical make-up in your growbed.  In the end, I also decided that zeolite may not really be the best choice.

[Louise]

Vlad - the person who contacted me imports zeolite from Turkey to Sweden. He might be able to send you a container too?

What do you use it for, where you like it so much?