Live Rock in my Freshwater Tank

[JDogg]

I am not talking about the coral and invert encrusted stuff that the Salties have....

but would a very porous rock, like say lava rock. provide any biological filtration... i would think that the holes would provide a good home for the freshwater bacteria, just like porous rock is used for filtration in SW tanks.

what do you think? :?

 

[7Enigma]

Of course! Any material that offers high surface area is great in a tank. Problems would be what happens to the water chemistry when added...

 

[Jarred Darque]

It would hold some bacteria that would benefit your nitrification cycle, same as any other decor or substrate in your tank. It just would not look near the same as the LR in a SW tank, unless maybe you got a piece covered iwth coraline, the coraline algae would die certainly, but the colors and all might remain and at least look nice.

 

[JDogg]

Of course! Any material that offers high surface area is great in a tank. Problems would be what happens to the water chemistry when added...

well i think lava rock should be rather inert chemically, i might be wrong. i have seen plenty of people use it in Rift Lake cichlid tanks.

i would use it as a additional bio-filter in my malawi tank

It would hold some bacteria that would benefit your nitrification cycle, same as any other decor or substrate in your tank. It just would not look near the same as the LR in a SW tank, unless maybe you got a piece covered iwth coraline, the coraline algae would die certainly, but the colors and all might remain and at least look nice.

i do not think that any rock that has coraline, i.e. grown in a SW tank would be good to add to a FW tank 8O

 

[Fishyfanatic]

I use it in all my tanks, it does not effect the water chemistry in the slightest.

 

[physicsdude]

Yes, lava rock is great in freshwater tanks. If you like, you can buy a small anubia and use a plastic twist tie to tie it to the rock. After 6 months or so, the roots of the plant will grow around the rock, creating a refreshing tropical look. I have done this with several and they all look faulous!

 

[JDogg]

the question is however... will it make a significant addition to my biological filtration...

i know some SW people do not use a filter, and use live rock in large quantities to biologically filter there tanks, could this be done is FW?

say i put 90 pound of Lava rock in my 45 gal tank and take off the filter...not that i would actually do this, but theoretical is it possible?

 

[Pleco]

I wouldnt. My old reef had no mechanical filtration, but i had somewhere in the neighborhood of 550-600lbs of LR and corals. I had a canister that i could use if i needed to, but short of using it in the very beginning i never really touched it after the LR cured.

I'm not sure Lava Rock can "cure" in the way that LR works but maybe i am off base on this assumption

-Pleco

 

[physicsdude]

No- it will not serve the same purpose as live rock. Live rock has millions of organisms all over its surface, that are native to the environment of the salty conditions found in oceans. Its an interesting idea, but its like comparing apples and oranges; the organisms that cause the rock to be called "live" rock do not exist in freshwater. Besides, the lava rock is good basically for biological filtration in filters only due to it having a large surface are where bacteria grow who convert ammonia and nitrite to nitrate.

 

[JDogg]

ok, it was just a thought i had...

 

[Jarred Darque]

I think I recall that one of the major differances between the good SW bacteria and the good FW bacteria, is that alotof your FW bacteria requires oxygen to thrive, hence the introduction of the bio-wheel or 'waterfall' filters where the water is poured over the bio media to create and oxygen rich enviroment

 

[Jarred Darque]

in theory though, if you provided enough surface area in the tank for bacteria to grow, then no, you would not need a filter except to remove particulate matter. This is kinda ismiliar to what most planted tanks have, they dont run biological filtration, just mechanical..of course, that is also to help keep CO2 levels high in the water

 

[Sicklid]

I have read that lava rock is SO porous, that it can eventually go anaerobic.

 

[rkilling1]

that is way plants provide such great biological filtration. Not only do they consume nitrogen from ammonia, but they also provide a hugh surface area for the colonization of bacteria. As mention previously, the bacteria in FW needs O2, where better to get it then from the plants?

Consider FW plants, the SW live rock.

(references http://www.aquabotanic.com/plants_and_biological_filtration.htm )

EDIT: sorry, forgot what forum I was in. (Back to the planted forum)

 

[rkilling1]

I have read that lava rock is SO porous, that it can eventually go anaerobic.

maybe you can use lava rock to convert NO3 to N2 gas?

 

[JDogg]

I have read that lava rock is SO porous, that it can eventually go anaerobic.

maybe you can use lava rock to convert NO3 to N2 gas?

except i want NO3 for my plants, but in a non-planted tank, yes that might be a goal, to eliminated or atleast decrease NO3 build up...

 

[jsoong]

I have read that lava rock is SO porous, that it can eventually go anaerobic.

That is only if you have no water circulation through them. Pond people use lava rocks as the filter media instead of expensive bioball, etc. Usually, this is in some kind of a wet/dry setup with lots of water flow so there is no chance of anything going anaerobic.

The denitrogenation idea is intruging .... anyone know if this work in FW? Anaerobic conditions in FW would tend to produce H2S & other nasties in ponds rather than N2 ... maybe plants or algae would be better choice as de nitrogenator.