Does volcanic rock "remove" nitrate?

[LeahK]

In an article on peacock gudgeons at http://www.petfish.net/kb/entry/86/, I read the following: "Volcanic rocks are added here for decoration and as a very beneficial aide to filtration. The volcanic rock acts as a nitrate removal system like the more widely used 'Live Rock' in saltwater tanks."
I don't know anything about saltwater tanks, but I thought that in freshwater tanks volcanic rock was just another place for ammonia- and nitrite-consuming bacteria to live, and that only water changes remove nitrate. But does the rock actually remove nitrates?

 

[excuzzzeme]

Volcanic rock is inert and makes a great mechanical filter. I sure don't know if or how it helps Nitrate removal.

I did a quick Google of using volcanic rock in FW aquarium and what I read supports the use of it as an aid in de-nitrifying.

 

[wataugachicken]

I don't think so. AFAIK, in saltwater the live rock doesn't remove nitrate anyway - it does the first two parts of the cycle, and then nitrate still have to be removed manually (water changes) or through the use of ANaerobic bacteria, which does its work without oxygen (like in a deep sand bed). i'm pretty sure that only anaerobic bacteria break down nitrates. i could be wrong though. additionally, even if something DOES remove nitrates, that does not affect the problem of total dissolved solids. water changes still have to be done whether nitrates are there or not. nitrates are just a general & easy-to-test-for marker to let us determine water quality.

 

[H3D]

It is said that anaerobic bacteria can grow in lava rock and remove nitrate. I have never done this, however I use Seachem Matrix in a similar manner.

 

[Reefscape]

I don't think so. AFAIK, in saltwater the live rock doesn't remove nitrate anyway - it does the first two parts of the cycle, and then nitrate still have to be removed manually (water changes) or through the use of ANaerobic bacteria, which does its work without oxygen (like in a deep sand bed). i'm pretty sure that only anaerobic bacteria break down nitrates. i could be wrong though. additionally, even if something DOES remove nitrates, that does not affect the problem of total dissolved solids. water changes still have to be done whether nitrates are there or not. nitrates are just a general & easy-to-test-for marker to let us determine water quality.

^ ^ ^ ^ Agreed

 

[jpappy789]

I don't think volcanic rock will support anaerobic bacteria. But anyways wata is correct that wc's are the only thing (other than live plants) that will remove nitrates.