Denitrification

[Mr. Fosi]

It's sort of like a birdhouse. Just put it there and you'll get what you want.

 

Good analogy, sorry I'm late.

 

I've been reading some of the stuff that lgreen put up (the marinedepot link is expired, BTW).

 

I like this idea of a plenum more than the RDSB and coil, though I am sure that they would all work.

 

Flatlander: I also wouldn't recommend the dosing of sugar, vinegar or vodka (ethanol, EtOH) on a regular basis. From what I have read, the nutrient reduction capabilities of these dosing agents is indirect. That is, they fuel the growth of all bacteria in the tank, not just the denitrifiers. The reason detectable nutrients are reduced it twofold: 1) they are locked in bacterial biomaterial and 2) flocculated or free-floating bacteria can be skimmed out. Not to mention that their use can lead to quick changes in tank parameters, especially in the small systems we are running. Also, dosing of carbon sources like this can lead to increased bacterial infection or stunted coral growth. Right now, I am playing with it in my exile/rock-cooking tank and it hasn't done jack for the nutrient levels.

 

Also, I have heard that good, porous LR does have anaerobic zones, but I haven't seen any really solid papers written about it.

 

Anderson: I thought that N2O was another side product of anerobic denitrification...

 

Icy: I think coils are neat and I like that they can be built very low-profile. What I don't like are the facts that 1) they need to be tuned very carfully, 2) that they need periodic maintenance (cleaning of valves or replacement of tubes), and 3) their effluent needs to be consistantly monitered.

 

I really like the idea of a remote plenum. If green's tank had been up longer, I would be asking more questions about its effectiveness and what he thinks about its usefulness.

 

Some of the reasons I like the plenum idea are: 1) they don't need to be replaced or cleaned every X years like an RDSB, 2) they require little maintenance, 3) they can be done remotely with little evidence that it decreases their effectivness, 4) they can be effectively be combined with a refugium thereby yielding the benefit (and coolness factor) of both, and 5) they can, apparantly, reduce the need for weekly waterchanges to monthly waterchanges. The only things I don't like about them are: 1) that they apparantly work better with coarser substrate, which I think is unattractive and 2) if you cut back your waterchanges then you will (depending on your livestock) need to dose Ca and trace elements.

 

It seems like a person could encorporate a 10-20g plenum/refugim into their system without much added equipment and therefore, for less $$. It doesn't seem that it would be useful to make a plenum/refugium of less than 10g if only for the reason that it would be difficult to get the gravel and water depth that is recommended.

 

Well, it seems that the initial topics of discussion have been addressed:

Q) Is biological denitrification worth trying for in a nano (6-55g)system?

A) Yes, but don't feel that you must do it.

 

Q) Do you think that coils or RDSBs would have any real value in a nano system, or are they just one more gadget that we would have to muck around with?

A) Yes, they will have a value and if done correctly, they shouldn't add much maintenance time/effort.

 

Q) Would a nano provide enough organic carbon to keep heterotrophic denitrifiers going or would you have to periodically dose methanol, EtOH, or sugar?

A) A nano should provide enough organic carbon and nitrogen to strike a useful balance in the system. Periodic dosages of external carbon sources may not be a bad idea, but it should also not be needed.

 

Q) Is there a size of nano that is too small for this to work?

A) In theory, no. One would have to use their good judgement when decideing to attempt a biological denitrification system.

 

Another thing that I realized while doing all this reading was that our 2lb LR/gal rule is called the "Berlin Method" of keeping a marine tank. There are other methods, such as "Jaubert's Method" whish has also been called the "Monaco System", which encorporate the plenum idea. I am not sure if there are any other names for the DSB method.

 

The issue in my mind now is, will I try this remote plenum method when I upgrade to a bigger tank?

[MrAnderson]

Anderson: I thought that N2O was another side product of anerobic denitrification...

 

It's an intermediate product in anaerobic respiration, but the final products are N2 and H2O:

 

N03- > N02- > NO > N2O > N2

 

edit: there are some bacteria that are considered "incomplete denitrifiers", do not have nitrous oxide reductase, and N20 is the sole terminal oxidant. But that's not really denitrification.

[formerly icyuodd/icyoud2]

Icy: I think coils are neat and I like that they can be built very low-profile. What I don't like are the facts that 1) they need to be tuned very carfully, 2) that they need periodic maintenance (cleaning of valves or replacement of tubes), and 3) their effluent needs to be consistantly monitered.

from what i gathered this is not the case (based on what i've been told/read)

" To accomplish nitrate reduction or eliminate the levels of nitrate that build-up in our closed saltwater systems you can buy a commercial denitrator that cost big bucks, is difficult to adjust, and requires feeding and monitoring to maintain proper operation. However, another very low-tech solution to very common nitrate woes is a coil denitrator! Essentially nothing more than a cylinder with a coil of tubing and some bioballs, this device works and achieves the same denitrification results as the more complex and costly commercial units, but much easier and more naturally"

 

"How a Coil Denitrator Works

A coil denitrator takes 5 to 6 weeks to cycle (yes, they cycle just like the tank). The quantity of product that is processed, (nitrate) is truly amazing, considering how once established there isn't anything more to do! So how does this happen? As oxygen rich water is pumped into (G) and enters the top of the unit (A) it is forced to spiral down through the layers of plastic coil tubing (E) until exiting within the center of the cylinder ©.

 

 

As the water level increases within the body of the unit, the bioballs (F) become host to the millions of colonies of bacteria that commence multiplying. As the water reaches back up to the top, it exits through the other fitting (, the one not internally connected that runs back to your sump or display tank. So? So, as the water slowly works it's way down the spiral, the O-2 is consumed by the AEROBIC (living only in the presence of oxygen) bacteria, the same ones that are in your filter and make all the life possible. Somewhere around 3/4th's of the way down however, the O-2 levels diminish within the spiral, having been consumed by the aerobic bacteria higher up the coil. (D=Base)

Now what? Well, now the ANAEROBIC (can live in the absence of atmospheric oxygen) bacteria begin to flourish, the very ones that feed on nitrate, not O-2! As the water continues its travels it encounters the main interior chamber of the cylinder. All those bioballs are just waiting to provide area for more anaerobic bacteria to consume all the nitrate that wasn't converted inside the bottom 1/4 of coil. This is the "bank" that will allow the coil denitrator to continuously process more and more nitrate as it is produced within the display tank. By the way, if you are using a wet-dry or trickle filter with ANY media, you have a nitrate "producing" filter! Yup, that's what they are designed to do, convert ammonia ultimately into nitrates! Nothing like adding more in so we can spend more money to get it out, huh? "

 

i was told, as long as you have a slow enough flow through the coil, they were pretty much maintanece free. the older they get, the better they work.

 

was i wrong to assume its that easy.lol

[lgreen]

Yeah, my tank hasn't been up long enough, but I am confident it works.

 

I wish I had a pic of my uncles tank, his is litterally proof they work. 125g SPS tank running strong for 11 years.

 

Almost every tank on http://www.garf.org is run by plenum. These people are amazing. They have been running plenums w/ boise, idaho tap water for like the last 30 years and produce coral like you wouldn't believe.

 

More plenum based tanks from Idaho:

 

http://www.idahoreefs.org/ReefTour2004/Sco...ott_Morell.html

 

http://www.garf.org/scottnewlook/scottnew.htm

 

http://www.garf.org/ScottCorals/scottcorals.html

 

http://www.garf.org/mark/MARK.html

 

http://www.garf.org/mark/xenia/xenia.html

 

http://www.garf.org/news24p2.html#TOM

 

oh and just for fun, look at this guys tank (run by pc lighting, no plenum, but awesome given the lighting):

 

http://www.idahoreefs.org/Gallery/Mick/Randy_Mick.asp

 

 

The plenum really appealed to me because every tank I have seen with them has been stuffed far beyond its limit w/ no problems at all. Plus if you get busy doing stuff (like school), you can leave these tanks for months w/ out water changes w/ little or no effect.

[Mr. Fosi]

Anderson: I get it now, that makes a lot more sense.

 

Icy: Depends on what you read I guess. I read stuff in Advanced Aquarist and over at RC and I got conflicting views. Of course, you never know what a person's setup really looks like. They could be leaving out key details that would reveal why they found complication with their coil. On the other hand, proponents of it may gloss over some of the tweaking problems. Bottom line: People in the coil camp think it is the best thing ever and people in the non-coil camp often claim that they tried coils and had problems. The problems usually cited are either unfavorable end products or a disproportionate (unexpected?) amount maintenance.

 

Green: You live in Idaho and have seen tanks (particularly your uncle's) run with these setups for extended periods of time... That is what sells me on this idea.

 

Experience is better than 'expert' opinion, such as you find in the RC threads. Don't get me wrong, I think that Calfo and Farley have a lot of great experience and knowledge, but I am not willing to go on just their word(s). I think that you have less reason to inflate the benefits of this system because your reputation isn't riding on it, like it is for some others.

 

Plus, if it is true that, "if you get busy doing stuff (like school), you can leave these tanks for months w/ out water changes w/ little or no effect", then it is going to be a windfall for me. When I start school this fall I am going to be jammed between classes and teaching labs. I don't think I am going to have much time for my tank, but I don't want to have to get rid of it and I don't want my animals living in squalor.

[lgreen]

Green: You live in Idaho and have seen tanks (particularly your uncle's) run with these setups for extended periods of time... That is what sells me on this idea.

 

Experience is better than 'expert' opinion, such as you find in the RC threads. Don't get me wrong, I think that Calfo and Farley have a lot of great experience and knowledge, but I am just not willing to go on just their word(s). I think that you have less reason to inflate the benefits of this system because your reputation isn't riding on it, like it is for some others.

 

Plus, if it is true that, "if you get busy doing stuff (like school), you can leave these tanks for months w/ out water changes w/ little or no effect", then it is going to be a windfall for me. When I start school this fall I am going to be jammed between classes and teaching labs. I don't think I am going to have much time for my tank, but I don't want to have to get rid of it and I don't want my animals living in squalor.

 

Agreed. I have seen tons of berlin systems and lots of plenums systems. I will never go back to the berlin method. DSB have potential, but are still a little flakey if you ask me.

 

That was a major reason for going w/ the plenum system too. When I get busy w/ school work, sometimes I don't even touch my tank for 2-3 months (besides feeding, top off, doing). It has made life a lot easier as well producing better results than any berlin system I have had.

 

Just set it up correctly! Use that article by Sprung as your guide.

 

Most important:

-need 1" plenum space at minimum

-need 2-4mm sand (caribsea special grade reef sand works perfect)

-needs to be at least 4 inches deep

-edit: never vacuum, never stir, never expose plenum space

 

also look at the instructions of www.garf.org. they use a riser pipe like an ug filter to get the plenum going and then cap it off after a month or two.

[MrAnderson]

Agreed. I have seen tons of berlin systems and lots of plenums systems. I will never go back to the berlin method. DSB have potential, but are still a little flakey if you ask me.

 

In my opinion there's no "right", "wrong" or "better" way to do natural nitrate reduction. All these methods work well and require little/no maintenance if designed, implemented and equilibrated properly. This is because facilitating denitrification is very simple; as I said, just put out a birdhouse and you'll get birds. It doesn't need to be as complicated as dosing vodka or building a complex apparatus.

[mtfish]

Oh, very good discussion indeed. I just wanted to put my 2¢ into the mix. I believe in Keep It Simple Stupid. If your nitrate levels are acceptable with your current maintainence routine, there is no need to mess around with the coils or RDSB. If your current maintence is working and you have a healthy system why risk it.

 

Regarding the dosing of nutrients to establish the bacterial colony, I would also say it would be better for it to equalize to the bioload naturally.

 

With all that being said, I often dream of the super low maintence tank that can just run and run. Then I wake up and find myself doing weekly water changes.

 

At somepoint in the future I plan on trying a coil denitrification setup for my 90g African cichlid tank. I'll have to make the results of that test public

 

And the final thing I wanted to mention was in your original drawings the picture on the right with the tube into the bottom of the bucket is just a Fluidized Bed Filter (as I understand things). The aerobic bacteria colonize on the sand particles, way more surface area that bio-balls from what I've read. Like Mr Anderson said (I think it was him), there would be too much oxygen.

 

Sorry this is kind of scatter brained. I thought of lots to say as I was reading then had trouble remembering it all.

[Mr. Fosi]

I'll jump in before Anderson tears any new 'ones'.

 

If your current maintence is working and you have a healthy system why risk it.

 

Because there is no risk with a RDSB. There is some risk to a coil, which is why I shy away from it.

 

With all that being said, I often dream of the super low maintence tank that can just run and run. Then I wake up and find myself doing weekly water changes.

 

Possibly because you have never tried any of these. I know 4-5 local reefers who keep large tanks with standard DSBs. They have corals and fish and they do monthly, or bi-monthly water changes in addition to dosing.

 

At somepoint in the future I plan on trying a coil denitrification setup for my 90g African cichlid tank. I'll have to make the results of that test public

 

Please do. We could all benefit from some solid reporting of first-hand experience.

 

And the final thing I wanted to mention was in your original drawings the picture on the right with the tube into the bottom of the bucket is just a Fluidized Bed Filter (as I understand things). The aerobic bacteria colonize on the sand particles, way more surface area that bio-balls from what I've read.

 

The part about aerobic bacteria in fluidized filters is right, but it wouldn't be fluidized. You'd have to move many thousands of gallons per hour through a 5g bucket filled with that much sand to make it fluidize. Water would be dripped into the center tube and allowed to percolate up through the sand.

[mtfish]

The part about aerobic bacteria in fluidized filters is right, but it wouldn't be fluidized. You'd have to move many thousands of gallons per hour through a 5g bucket filled with that much sand to make it fluidize. Water would be dripped into the center tube and allowed to percolate up through the sand.

 

I'm always worried about getting ripped when I post anywhere

 

I must have missed the part about dripping the water. I understand what your saying but I think the 1000s of gph is a little exagerated. But that would be a different (and pointless) thread because I'm not trying to start a arguement.

 

And yeah your right about me not using a DSB or RDSB. The 10g nano I just started setting up doesn't require that But in the future I would like to try a DSB or RDSB. Anyway I'll blah blah all night if I don't stop now, Like I said before good/interesting topic and keep us up to date on your RDSB.

[Mr. Fosi]

... keep us up to date on your RDSB.

 

You mean plenum. I think I am going to chuck the RDSB idea.

 

This whole page of posts has been devoted to plenums.

[mtfish]

aww jeez.

 

That was a quick update.

 

Keep us up to date on whatever happens with anything. I promise I'll shut up and sit quitely in the corner.

[MrAnderson]

So you're going to do a plenum now?

 

All those plenum tanks look like they have a lot of algae. Hard to tell from the pics, but there's a lot of green on the rocks.

 

I've always thought plenums are a good method for denitrification, but bad for phosphate reduction. Also more complicated than is necessary in my opinion. In this respect I do agree with mtfish's adage "keep it simple".

 

To each his own. As I said, I don't think there's a "wrong" way, but really a matter of taste. Have fun

[Mr. Fosi]

So you're going to do a plenum now?

 

I haven't made a commitment. I said I was "sold on the idea", but that means I am willing to draw up a plan for it. Whether I actually do it is another question alltogether. So many people like to make a quick choice and get running with it, but I prefer to take it slow and mull it over. I am always suprised with the number of problems I can thwart before I even begin contruction just by taking a little more time to think it through.

 

I can fly blind, but I always prefer to have a well thought out design before I start trying to set up a new system. Before I draw up a plan, I always pursue and discuss my options, and so here we are.

 

To each his own. As I said, I don't think there's a "wrong" way, but really a matter of taste.

 

I agree (yet again). Since all the aformentioned methods will work, it is really a matter of which one I like the most. Right now it is the plenum, but if new facts come to light I am ready and willing to reconsider the other options.

 

In this case, it is really going to be a matter of how much room I am going to have to work with. Since I don't know what kind of place my wife and I will have when we move, I can hardly make a firm choice about which to use.

 

Of course, the idea of baby-proofness is going to factor in too, given we are expecting a child in October. Since the tank'll probably still be running when the kid is old enough to walk, I should probably start thinking about how I can keep his/hers hands out of it.

[lgreen]

So you're going to do a plenum now?

 

All those plenum tanks look like they have a lot of algae. Hard to tell from the pics, but there's a lot of green on the rocks.

 

I've always thought plenums are a good method for denitrification, but bad for phosphate reduction. Also more complicated than is necessary in my opinion. In this respect I do agree with mtfish's adage "keep it simple".

 

To each his own. As I said, I don't think there's a "wrong" way, but really a matter of taste. Have fun

 

It's just the pics. It is typicall to get a nice thick film of algae on the glass each week, but other than that, usually no green algae.

 

There really is nothing complicated about a plenum. Heck you can buy premade plenums. Set it and forget it.

 

Anyway do what ever you want mr. fosi. You just have to do what will work best for you.

[MrAnderson]

There really is nothing complicated about a plenum.

 

Building it looks time consuming. Not to mention the trip to Home Depot, grrrr, I hate HD.

[lgreen]

There are a few companies out there that build them.

 

It took me maybe an hour or two to build mine. Not that bad.

[mtfish]

Not to mention the trip to Home Depot, grrrr, I hate HD.

 

Go to Lowes.