Live rock in Freshwater?

[knifegill]

I like deep sand beds and pothos vines, etc, personally. But to get anaerobic activity in lava rocks, make sure to get very light, fine-pored rocks, not the glassier heavy ones. Alternatively, a media does exist which does this very thing. I forget the name, but it's a large grade of media, like stones, meant for ponds. Somebody will chime in. But the answert is - Yes, anaerobic denitrification works well in freshwater. It's a matter of application.

 

[carsona246]

However, unlike saltwater, freshwater does not contain a strain of bacteria which will convert your no3 into n2. So your nitrates do not get converted to nitrogen gas like in a saltwater aquarium.

are you sure about this?

 

[Redearsunfish]

I have no scientific proof no, but i use it for looks anyway.

 

[carsona246]

has anyone personally cultivated anaerobic bacteria in a freshwater tank using rocks?
Redear, have you ever noticed a lower nitrate level in tanks with lava rock? I'm getting pretty curious now if this is possible or not, I keep reading conflicting posts. Some people claim it's possible to grow denitrifying anaerobic bacteria in freshwater, and others claim it's not possible.

 

[Oughtsix]

I have not come across anyone pitching the wonders of using porous rock for removing nitrates in fresh water. That doesn't mean it isn't possible and that certainly doesn't mean it can't happen.

I am pretty sure there is some strain of anaerobic bacteria that will colonize in fresh water (probably not the same strain as the salt water strain). Nitrate consuming anaerobic bacteria is the basis for deep sand bed filters and nitrate reactors both of which I have heard of being used successfully for fresh water aquariums. I think there are just better, more cost effective ways to remove nitrates from fresh water in most situations.

Fresh water is usually a lot less expensive than salt water so most people just change the water to remove the nitrates. I have read some articles pitching the idea that water changes also refresh the supply of essential trace elements... but haven't seen any overwhelming evidence as to the validity of this claim. Some people do have to contend with Nitrates in their source water though!

There are a lot of terrestrial plants that will consume nitrates. Pothos being a popular one that I also use myself. I don't believe there are as many salt water hearty plant species available.

The Ultra efficient super algae Nitrate filter looks like a cool Nitrate reducer also... I am just too lazy to implement something so elaborate.

I guess my advice would be to give it a try and monitor your Nitrate levels. Your results if documented well can add to the accumulated knowledge of fish keeping! Finding out that porous rock isn't an effective Nitrate control method is just as valuable a result as finding out it is. Maybe everyone else that has tried it has abandoned the idea and never bothered to record why?

 

[carsona246]

I think I'm gonna have to setup a new tank and see if I can't get some nitrate reduction going with some rock. If anyone's tried this though, I would love to hear how it's worked for them. I do use planted filtration in all my tanks, but I like the idea of using rocks for nitrate removal as well

 

[jonny5]

i will be honest, im not certain about freshwater not having the anaerobic type of bacteria to convert to N2, but i have looked up this same topic and found no evidence of such thing, it would be very cool if you could find a certain type of rock and just rock some powerheads like they do in saltwater.

However, plants are freshwaters nitrate removers, even in a "non planted tank" you can throw in some hearty lwo light plants that will do some nitrate absorbing.

 

[carsona246]

I'm not arguing that plants are not effective nitrate removers at all. I have large amounts of pothos/peace lilly in every single one of my tanks. But there is no reason to not explore every option available. So if it's possible to cultivate anaerobic bacteria to get rid of nitrates, why not add the extra filtration? Especially when it could be as simple as adding some lava rock/texas holey rock
I'm still searching for some answers, can't seem to find anyone who has attempted this. However, it seems logical that if a freshwater dsb works on the principle of anaerobic bacteria removing nitrates, than it would work the same with using rocks.

 

[pk705]

One thing you should count into your equation is the fact that a) reef tanks have huge water movement and b) they're stocked lightly with a lot of live rock. In other terms, if you are going for a fish tank with a high bio load (I'm assuming this is why nitrates are problematic?), your plan is going to fail, similarly as live rock filtration is usually not the only filtration employed on large FOWLR tanks.

 

[jonny5]

I'm not arguing that plants are not effective nitrate removers at all. I have large amounts of pothos/peace lilly in every single one of my tanks. But there is no reason to not explore every option available. So if it's possible to cultivate anaerobic bacteria to get rid of nitrates, why not add the extra filtration? Especially when it could be as simple as adding some lava rock/texas holey rock
I'm still searching for some answers, can't seem to find anyone who has attempted this. However, it seems logical that if a freshwater dsb works on the principle of anaerobic bacteria removing nitrates, than it would work the same with using rocks.

that is if a freshwater DSB really exists, with the exception of that gentelman earlier in the thread i have never heard of an effective freshwater DSB. I did some google searching about this subject a few months ago and came up with nothing. If you find some definitive answers, please inform us all