Why does a tank with Live rock accumulate Nitrate?!?!

[10" Red Devil]

Hello,

This is something I just thought about the other day and was wondering why other then heavy bioload and not enough live rock would a live rock filtered tank have high nitrate. I mean arent there bacteria (sorry forget the scientific name for the nitrate reducing or eating bacteria) that take care of nitrate that come in on ones live rock?

Thanks.

[MCary]

There is not enough nitrate reducing bacteria (anaerobic nitrospira I believe) in live rock for it to be a complete nitrate removing system. The rock would need to be large and pourous without alot of oxygenated water circulating around it. That's why other nitrate reducing systems are used. DSB, nitrate reducing reactors, refugiums, or in the case of BB nutrient control. If your counting on just liverock fixing the problem it ain't gonna happen.

Mike

[skeeter_ca]

Ditto to MCary

[mthedude]

Live rock basically acts as a better bio ball, great at removing Amonia and Nitrite but not that great at reducing Nitrate, that's where the DSB, Skimmer and Fuge come in, along with water changes.

[jimbo045]

I think mine are high with mainly live rock, around 50. But it looks fine. JD

[10" Red Devil]

Well I dont have a problem, but I got into a discussion with my lfs owner about this.

It all started when I wanted to know if he had the new (Fe based) Po4 remover. He knew I had already bought a jar of Rowaphos from him previously and wanted to know why I was unhappy with it. So I told him how it has these fines that are tricky to get rid of, plus it does not work well in the two little fishies reactor. I told him how I thought about using fliter floss in addition to the sponges, but that I was afraid of a nitrate build up. He stopped me at the point and asked how that would cause a nitrate problem. Well in my limited scientific knowledge I exclaimed that it would cause a condition similar to a wet/dry which are known nitrate factories. He then said that my Live Rock would take care of any nitrate problems because of those anaerobic nitrospira that MCary so elequently pointed out are supposed to take care of this.

This got me thinking about basic things that I have overlooked in my experience or taken for granted and I wanted to know.

Thanks.

[Travis L. Stevens]

<a href=showthread.php?s=&postid=7383636#post7383636 target=_blank>Originally posted</a> by mthedude
Live rock basically acts as a better bio ball, great at removing Amonia and Nitrite but not that great at reducing Nitrate, that's where the DSB, Skimmer and Fuge come in, along with water changes.

I disagree. They are great at breaking down all organics. Deep inside the rock is where the denitrification is processed, but the outside is good for ammonia and nitrite break down.

[reverendmaynard]

As I understand it, the problem with bio-balls, floss, sponges, and any other media that can only break down ammonia and nitrate is that once the nitrate is in the water column, it won't be broken down further in significant quantities by denitifying bacteria. For some reason, and I'm not sure what it is or if the theory is even proven (IIRC, it has something to do with local contentrations of nitrate), the denitfrication needs to take place in close proximity of the nitirification for optimal results.

[Tomzpc]

<a href=showthread.php?s=&postid=7383526#post7383526 target=_blank>Originally posted</a> by MCary
There is not enough nitrate reducing bacteria (anaerobic nitrospira I believe) in live rock for it to be a complete nitrate removing system. The rock would need to be large and pourous without alot of oxygenated water circulating around it. That's why other nitrate reducing systems are used. DSB, nitrate reducing reactors, refugiums, or in the case of BB nutrient control. If your counting on just liverock fixing the problem it ain't gonna happen.

Mike

I totally disagree with this statement. I've been keeping tanks for about ten years without deep sand beds, refugiums, reactors etc. and my nitrates have always been undetectable. On top of that I've never been as religious about water changes as I should or would like to be. IMO and IME, suitable amount of live rock (I'd say at least 1 lb per 2 gallons) coupled with good in-tank water movement should suffice in keeping nitrate levels at or near undetectable, assuming the bio-load isn't too heavy, the tank is reasonably skimmed and regular water changes are made.

[phallock]

<a href=showthread.php?s=&postid=7383953#post7383953 target=_blank>Originally posted</a> by Tomzpc
I totally disagree with this statement. I've been keeping tanks for about ten years without deep sand beds, refugiums, reactors etc. and my nitrates have always been undetectable. On top of that I've never been as religious about water changes as I should or would like to be. IMO and IME, suitable amount of live rock (I'd say at least 1 lb per 2 gallons) coupled with good in-tank water movement should suffice in keeping nitrate levels at or near undetectable, assuming the bio-load isn't too heavy, the tank is reasonably skimmed and regular water changes are made.

You've confused me, what's to disagree with? You're basically saying the same thing, that live rock alone won't completely remove nitrate.

[physicslord]

As a last resort there's always the "bio-denitrator".

Kind of a crutch, but if you are running too many fish then it might make a big difference.

And 50ppm is pretty high for fish. That will encourage algae growth.
The legal limit for nitrates in tapwater around here is 45ppm.

[mthedude]

If live rock would process Nitrates to undectible levels then everyone in the hobby would have no problems with nitrates, there is more surface area on rocks that are home to aerobic bacteria and much less area with anaerobic bacteria since water can reach most places inside a porous rock where the anearobic baceria live, hence water changes, macro algae culivating, skimming and DSB's are helpful in reducing nitrate levels

[boxfishpooalot]

The way I see it is it's hit and miss for live rock. Some come porous right through the entire rock, with channels, worm holes ect. But some(like mine) are just solid chunks of rock with the surface containing small holes, but not nearly enough external surface area to reduce nitrates to undectable. But, if my rock was sort of like a sponge, with micro pores I could do without my sandbed.

Interesting thread-i thought the same thing.

[MCary]

If live rock would process Nitrates to undectible levels then everyone in the hobby would have no problems with nitrates

This is what I'm talking about. I don't know how many threads I have read where a person says (composite paraphrased example post) "I have 100 pounds of live rock and still my nitrates are over 20 ppm, what am I doing wrong?"

I have drilled into live rock and found a sludge like mud in the center of some. Kind of like a ROLO candy. I might expect that rock to act like a DSB. But alot of rocks don't have that, alot are too small or not pourous enough. I would say that anyone who has undectable levels of nitrate from liverock alone is just lucky.

Miek

[Amphiprion]

There plenty of denitrification processes that occur within the pores of live rock. However, density of the rock, fish load, etc will have a significant effect on the overall capabilities. Due to metabolic constraints (i.e. oxygen, obviously not nitrate in many cases), they can only extend to certain regions. While denitrification action may be heavy, it often isn't enough to cope with the above factors. BTW, Nitrospira are primarily aerobic and only oxidize the nitrite ion. There are many species that do this, but I don't think Nitrospira does.

[omni2226]

Water doesnt move through the rock on its own regardless of flow rates. It gets moved by the animals living inside it.

One factor that may explain why some rock "outpeforms" other rcoks in denitrating is the amount and diversity of critters living in the rock, and since every tank is diffrent some people may have greater diversity or larger populations of these critters in their rocks.

Look closely and see if you have lots of bristelworms, micostars, stometella, pods and so forth moving in and out of the holes.
Low populations and/or lack of diversity could hinder the denitrate process.

I have been thinking a lot about the biological side of things here lately and Im starting to lean toward the idea that relying on live rock as the backbone biological filter may not be the best idea.

People with large refugiums (in relation to system size) seem to have less problems with nitrates. Maybe its from the sandbed, or predator free "healthy" live rocks. Those of us like myself who dont have refugiums may need to look at other alternitives to denitratying.

I have a deep sand bed in my display for this but and so far have had no readable nitrates since the first week of the cycle. Those who dont want a sandbed may have to resort to mechanical means like a denitrator.
These arent cheap to buy but with a little thought (large plastic can with a very small pump and sand) could be home made.

My two pennies.

[Amphiprion]

yes, thank you Omni, that does indeed make a difference (sorry I left it out). This would go along with metabolic constraints, in that it would affect the amount of the needed nitrogen sources reaching bacterial colonies. Yet another reason why bristleworms and relatives are so important.

[MCary]

BTW, Nitrospira are primarily aerobic and only oxidize the nitrite ion. There are many species that do this, but I don't think Nitrospira does.

That's correct. I was going to post a retraction after realising what I had written. Nitro Spira are aerobic bacteria which are highly efficient ammonia reducers but produce nitrate as a biproduct. They function very well in highly oxygenated environments like wet/dry filters. The other aerobes, the ones that colonize filters, liverock and sand are mainly nitrobacters and nitrosomas. I don't know the name of the anaerobes.

As for the critters in the live rock. I don't think so. Anaerobic places are basically dead zones where nothing but the bacteria can live. Critters stir the top layers of a DSB and may open pores to lower levels of LR. But I think that's the extent of it. But as always, I could be wrong.

Mike

[Amphiprion]

As far as Nitrospira sp. are concerned, I was thinking that there may have been some study I missed or something. I am glad you cleared it up for me as well, as there are always exceptions somewhere.

You are correct in your assumption that these animals do not really travel into anaerobic regions of the live rock. However, the activity in the outer layers causes a certain amount of turgor, thereby moving small amounts of water through rock structures. The more water (up to an extent of course for anaerobes, since it would introduce too much oxygen) that is moved, the more efficient the process will become (thus more nitrate removal as well as other metabolites). However, even without animals, there are some diffusion processes (VERY slow, really too slow) that would otherwise move nutrients throughout the rocks.

[mm949]

if the core of the rock is pack with dirt...you will not denitrate and your po4 will go up...the key is keeping the vains open...you should use a small power head to clean out the vains and remove the dirt...good water flow from behind the rock will make sure no dead spots occur....having a spread out rock formations will help also.....

[Tomzpc]

<a href=showthread.php?s=&postid=7384116#post7384116 target=_blank>Originally posted</a> by phallock
You've confused me, what's to disagree with? You're basically saying the same thing, that live rock alone won't completely remove nitrate.

No. I said just the opposite.

Mccary said this: There is not enough nitrate reducing bacteria (anaerobic nitrospira I believe) in live rock for it to be a complete nitrate removing system.

I disagree with that statement based on ten+ years of reefkeeping experience. I've had a few tanks over the years and none have ever had a deep sand bed, a refugium or a denitrator.
So where are all of the nitrates going? Apparently my live rock is a complete nitrate removing system. =)

[omni2226]

Just curiuos about the animal thing tom, do you have a lot of worms and things in your rock? Everything I have researched about deepsand beds and rock point to the animals moving the water up down and in and out of the rock and sand.

[Tomzpc]

<a href=showthread.php?s=&postid=7383435#post7383435 target=_blank>Originally posted</a> by 10" Red Devil
Hello,

This is something I just thought about the other day and was wondering why other then heavy bioload and not enough live rock would a live rock filtered tank have high nitrate.

Back to the original question. It could be a number of things. Too much feeding? Not enough waste dilution through water changes and skimming. Not enough flow? If there is a high level of detectable nitrates I agree that further action need be taken such as adding a refugium(as a macro filter) or using a product like AZ-NO3, but if nitrate levels are barely detectable than IMO and IME you don't NEED a refugium or a DSB or a denitrator to reach and maintain undetectable nitrate levels. Everyone else here seems to disagree though so take what I say with a grain of salt. ;)

[Tomzpc]

<a href=showthread.php?s=&postid=7386029#post7386029 target=_blank>Originally posted</a> by omni2226
Just curiuos about the animal thing tom, do you have a lot of worms and things in your rock? Everything I have researched about deepsand beds and rock point to the animals moving the water up down and in and out of the rock and sand.

I have very little "visible" life in and around my rocks probably because of my fish choices over the years. I don't necessarily agree with the premise that water has to be moved through the rock by animals in order for it to reach anaerobic areas. I recall Dr. Shimek making that statement in an article awhile back. I feel that strong currents such as we have in a reef tank will do the trick.

BTW, I also think that DSB's add more nutrients to a system than they remove and I don't know diddly about biology so obviously my comments are heresy anyway. LOL. But I do know that many reefers agree with me.

[Tomzpc]

<a href=showthread.php?s=&postid=7386029#post7386029 target=_blank>Originally posted</a> by omni2226
Just curiuos about the animal thing tom, do you have a lot of worms and things in your rock? Everything I have researched about deepsand beds and rock point to the animals moving the water up down and in and out of the rock and sand.

I have very little "visible" life in and around my rocks probably because of my fish choices over the years. I don't necessarily agree with the premise that water has to be moved through the rock by animals in order for it to reach anaerobic areas. I recall Dr. Shimek making that statement in an article awhile back. I feel that strong currents such as we have in a reef tank will do the trick.

BTW, I also think that DSB's add more nutrients to a system than they remove and I don't know diddly about biology so obviously my comments are heresy anyway. LOL. But I do know that many reefers agree with me. It just isn't apparent in this thread.

[omni2226]

It makes this hobby fun, all the diffrent ideas and opinions. Be kinda boring if there was only one way to do things dont ya think?

So go on, be a heretic. I promise to use only the best gasoline when we burn ya at the stake. :)

[Amphiprion]

<a href=showthread.php?s=&postid=7386089#post7386089 target=_blank>Originally posted</a> by Tomzpc
I have very little "visible" life in and around my rocks probably because of my fish choices over the years. I don't necessarily agree with the premise that water has to be moved through the rock by animals in order for it to reach anaerobic areas. I recall Dr. Shimek making that statement in an article awhile back. I feel that strong currents such as we have in a reef tank will do the trick.

BTW, I also think that DSB's add more nutrients to a system than they remove and I don't know diddly about biology so obviously my comments are heresy anyway. LOL. But I do know that many reefers agree with me. It just isn't apparent in this thread.

What you are saying is not heresy--merely incomplete. Yes, water circulation does help reach some areas, but not quite to the extent as smaller organisms can deep within the rock. Both good flow and animal diversity are important in this situation, as they bring both nutrients for bacterial action and waste/dead bacteria from various pores. As far as the DSB thing goes, there are too many variables involved that would determine the success or failure of such an analog that it would be difficult to discuss and, in many cases, replicate.

[omni2226]

The sand bed thing is new to me. I have kept many freshwater tanks and nitrates are dealt with by the plants. In cichlid tanks heavy duty filters and mega water changes.

I kept a marine tank for about 18 months but it had no rocks or sand, just crushedcoral/oyster shell with a undergravel filter.

No corals just one lonely Lion fish. Im open for ideas and new things. I did a lot reading and decide on a deep sand bed this time but I may try a barebottom setup on the next large tank.

Im not quite brave enough or yet know enough to pull the sand in this one. If it aint broke dont fix it, and mine aint broken yet.

First I want to get a 29 seahorse tank going with black sand and,,,,well thats in the future.

[zeuss zoso]

I have high nitrates on my 60gallon. I have 2 canister filters, and several scattered powerheads. Do you think the canisters are making higher nitrates. I am going to add a sump/ fuge but would rather not because I have to dril the tank with everthing in it.
Alex

[zeuss zoso]

I am wondering why I have such high nitrates. Around 20-40ppm. I have two canister filters, and several powerheads. Could the mechanical filtration in the canister be a nitrate factory? The algae problem is bad, I have to scrape glass every day. That tank has been up for 3 and a half months. I have 5 fish, and 5 corals. Think I should add a fuge? I am seriously considering adding a sump, and using the canister filters just for filtration and taking everything out of them. Alex

[Amphiprion]

The mechanical filtration, if not cleaned or replaced very regularly, will lend to the problem. You may also want to back off on feeding a bit. Do you have a protein skimmer? A refugium can also help, as well.

[zeuss zoso]

i have a seaclone 100 and i feed everday one cube of mysis or spirulina

[Amphiprion]

I don't think you should have to feed everyday with the fish you have. I would reduce to every other day for the time being. You may even want to try every two days (just watch the fish and make sure they maintain their weight). Is the seaclone working well for you? You may want to consider a different skimmer, such as the coralife super skimmers.

[zeuss zoso]

I have 2 tangs, kole and yellow. They need a lot of food. The seaclone is kinda crummy. Lol. It is fine, once I get my fuge. I think it will help tons, and I am going to have about 800 gph more of flow once i add it.

[boxfishpooalot]

It all comes down to the density of rock(how many holes inside it) .

[mthedude]

Tomzpc, are you saying in 10 years of reef keeping you have had no form of nutrient export other than your Live Rock and your nitrates are undectable?

I think we're all in agreement and we just don't realize it. If there is anyone running a reef tank with no DSB, no fuge, no skimmer and only rely on Live Rock for filtration I'd like to see it and would love to know what thier Nitrate reading is. We don't just add skimmers to add oxygen to the water and we don't have refugiums just to watch the pods play all day, our live rock needs those extra support systems to help complete the cycle and remove nitrates from our systems.

[boxfishpooalot]

<a href=showthread.php?s=&postid=7387733#post7387733 target=_blank>Originally posted</a> by zeuss zoso
I have high nitrates on my 60gallon. I have 2 canister filters, and several scattered powerheads. Do you think the canisters are making higher nitrates. I am going to add a sump/ fuge but would rather not because I have to dril the tank with everthing in it.
Alex

What kind of sand? Fwiw crushed coral is a bad size to perform denitrication.

[Ovaltine]

two words, seachem purigen, absolutely the best stuff to come out in years, buy it in the bags, last 6 months and can be reenergized easily. this stuff takes nitrite and nitrate down to zero. plus it takes a whole host of other things out of the tank water. it's the best stuff to come out in years. buy it in the bags and drop it in your sump under the eggcrate holding the bioballs. in a week you'll see nitrates disapear. try two little bags for your size tank. i swear by this stuff. if you don't get o nitrite and nitrate in a week, then you must have your toilet plumbed into your tank without knowing. that's how good this stuff is.