# Denitrification in Freshwater Tanks



## Vucko (May 9, 2009)

I used to have several salt water reef tanks and one live rock live sand fish only tank. The substrate I used was a fine sugar coral reef sand (From ESV Co.) at a depth of about 1/2 to 1 inch. I found that even the fish only tank experienced complete denitrification with this setup.

When I moved and got rid of all of my reef stock, I set up two of the tanks for Tanganyikans with the same sand and rock that I had in the reef tanks. I was curious to see what would happen with the nitrogen cycle. The water chemistry stays perfect and the tank surprisingly goes through complete denitrification.

I've had the tanks set up for about five years and I change the water about twice a year. I must also say that the reef rock provides for great habitat for the fish and brings out interesting behavior. Just thought I'd pass this along.


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## illusions2281 (Jan 25, 2009)

i'd like to know more about this. how much rock per gallon? and are you saying that the live rock you had to change the fresh water twice a year? do you have pictures of this set up


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## prov356 (Sep 20, 2006)

> i'd like to know more about this. how much rock per gallon?


I wouldn't run out and buy a bunch of reef rock if I were you.

Just my .02


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## Vucko (May 9, 2009)

I have pictures. I didn't load up as much rock as I had in my reef tanks I'd say about 1 pound per gallon. From my experience the denitrification comes from the anoxic zone in the sand as much as from the rock.

From playing around with reef tanks for 30 years my own personal experience led to the use of about 1/2 inch of sugar sand. It's was deep enough to denitriy but not to collect detritis and form noxious pockets like plenum systems.

the tank I have pictures of is an acrylic integrated tank with the protein skimmers and mechanical filters built in to the back. for the Tangs and the couple of Malawi I have all I use is one sponge filter in the back for mechanical filtration. I use a turkey baster about once or twice a month to agitate the sand and blow off the rock to stir up the detritis so that it is caught by the mechanical filter. The same practice I employed when I had my reef tanks.

Somebody tell me how to upload a picture or two I will.


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## illusions2281 (Jan 25, 2009)

sounds ineresting. i just bought a 24 gallon nano tank. i was going to go with a deep sand bed. what type of sand & where to get it are you recceomend?

I have some extra live rock your saying its oke goo put that in my cichlid tank? arent the saltwater things on it going to die and rott and pollute the water at first?


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## Vucko (May 9, 2009)

The sand I have is oolitic reef sand from ESV Company. *Absolutely do not put the live rock from a saltwater tank into a cichlid tank.*

The rock I have was "out of water" for over a year between the time I disassembled my reef tank and started up my cichlid tanks. I have similarly started reef tanks the same way, with dry base rock and let mother nature establish the ecosystem on its own. Leroy Headlee from GARF has done the same thing with home made aragonite rock and aragonite rock mined from ancient reef formations in Idaho.

All I did was put in the rock and sand in the tank, added black mollies to cycle, then add the cichlid fish, and things have been on autopilot ever since.

If your nano is going to be saltwater, from my experience I would not add any more than 1/4 - 1/2 inch of sand. As I am sure that you are aware, many reef tanks do not even have any sand beds in them at all. I know alot of the top SPS reef guys and none of them use deep sand beds or plenums anymore. Most use refugiums with or without Leng Miracle mud systems, my buddy Mike Paletta for example. His 1200 gallon SPS tank is not covered with sand.

I just thought I'd bring attention to folks what has worked for me. So far I have not run across anybody who has used exact same rock and substrate and converted from saltwater to freshwater rift lake cichlid. I did it as an experiment because I enjoy watching fish and due to work no longer had the time to keep reef tanks. So far five years into it I've had no problems.


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## illusions2281 (Jan 25, 2009)

oh i see. thats making more sence now. I'm going to look up oolitic reef sand from ESV Company.


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## bntbrl (Apr 23, 2009)

*** used homemade reef rock in African cichlid tanks. I used a HOB filter though. There used to be a lot of controversy about the GARF thing, has it calmed down lately?

I dont see why it wouldnt work if your bioload was low. It really isnt much different than a wet filter is it? I had a 55 gallon with about enough aragonite sand to cover the bottom aesthetically. I pretty much had enough rock in it to have used it as a reef tank. The rock was made by me with portland cement and oyster shells for chickens. I never had any problems with freshwater, salt, or reef tanks. The amount of fish that I had in mine wasnt a large bioload I dont think. I didnt perform regular water changes either. Once a month or three or maybe more.


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## illusions2281 (Jan 25, 2009)

UPDATE:

Everyone who ordered sand please note that ESV has notified us that they have discountinued production of the Oolitic sand and are now producing a White Fine and Coarse grain sand. The price difference is only $6. Please let us know if you still want it. Thank you.

http://www.manhattanreefs.com/forum/ven ... esv-4.html

SO I suppose carbi sea oolitic sand is the only other option


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