Nitrate Factory

[wsonner]

Ok...this has bothered me for a long long time and I thought I would start a thread to discuss it. Certain filter types (eg. bio-balls) are said to be "nitrate factories". This indicates that somehow, given a constant bio load, a certain type of filter would produce a greater amount of nitrate over a given time period. Does this make sense? It has always seemed to me that the bi-products from a given bio load can only be decomposed into a fixed amount of nitrate regardless of the filtration type, although the time taken to decompose it might differ. Thoughts? Equations? Graphs?

Wes

[LockeOak]

I've always taken it to mean (and this is pure conjecture) that since bioballs are designed to maximize surface area, they serve as a substrate for aerobic bacteria that rapidly convert proteins, ammonia and nitrites into nitrate. This is generally beneficial as nitrates are less harmful than ammonia and nitrites, but it still leaves the nitrates behind. As the bioballs have high surface area and are impermeable there is no way for anaerobic bacterial communities that convert nitrates to nitrogen to build up as in deep sand beds or porous live rock. That is, bioballs leave out the last step of protein input -> ammonia -> nitrite -> nitrate -> N2, leaving higher nitrate levels than a DSB or live rock, which convert to N2. I guess the same argument could be made for dirty sponge filters. Therefore one could say that a filtration type either nitrifies (like a DSB or live rock) or removes the nitrogen compounds altogether (skimming, carbon) would be superior. I can't say if this is true, but it does seem to be a reasonable argument. (For the record my only filtration is 2lb. of live rock per gallon and a chaeto-filled refugium).

[jimmyj7090]

It's basically an issue of rapidly breaking waste down into nitrate, vs, creating a more balanced system so that waste is cycled, removed, and some broken down.

Wet dry type filtration is great at nitrification, but it turns everything into nitrate before any waste is eaten, absorbed, skimmed out, or otherwise managed via means other than nitrification. Add to that the fact that wet dry's have no de-nitrification capacity, they lead to a system where everything is turned to nitrate with no where for the nitrate to go except to build up.

Without the wet dry, waste is abosrbed by corals and other life forms, it is skimmed out before being broken down, and what is left over is broken down to nitrate but if things are in balance there is enough denitrification to finish that cycle.

(Three ways to word the same answer, hope it makes sense?)

[wsonner]

It's basically an issue of rapidly breaking waste down into nitrate, vs, creating a more balanced system so that waste is cycled, removed, and some broken down.

Wet dry type filtration is great at nitrification, but it turns everything into nitrate before any waste is eaten, absorbed, skimmed out, or otherwise managed via means other than nitrification. Add to that the fact that wet dry's have no de-nitrification capacity, they lead to a system where everything is turned to nitrate with no where for the nitrate to go except to build up.

Without the wet dry, waste is abosrbed by corals and other life forms, it is skimmed out before being broken down, and what is left over is broken down to nitrate but if things are in balance there is enough denitrification to finish that cycle.

(Three ways to word the same answer, hope it makes sense?)

Yes, this absolutely makes sense. What you are saying is that bio-balls are TOO good at their specific job, which is nitrification. So more nitrate enters the water because the filter breaks down waste too quickly and doesn't allow for the bio load to be reduced through other means (like skimming etc). In essence the net bio load being handled by the filter is greater so nitrate production is greater. That makes sense to me and is a much different picture than the one painted by calling it a "nitrate factory" because this implies (to me) that somehow it creates MORE nitrate for a given bio load and it really can't given the law of Conservation Of....well...Bio Load. :)

So when the wet-dry filtration method was really popular was live rock and protein skimming not available?

[jimmyj7090]

Wet dry filtration originated before there even was LR in the hobby. The wet dry approach actually, IIRC, came from sewage treatment.

As far as I know of the first person to begin to play with LR was Lee Chin Eng in Indonesia around 1960, but he was pretty much filling a buckett from the real reef and walking home and placing the rock in his tank. Commercial rock didn't come around until way later.

The hobby has advanced progressively since then.

Wet dry filtration was really revolutionarly for the hobby when people were only keeping fish and coral skeletons, systems with massive fish waste, virtually no biodiversity, and no concern with nitrate. Skimmers began to pop up around the same time, but they were nothing compared to what we have now.

Ca reactors, MH lighting outside of pee yellow industrial bulbs, Acropora living in captivity, and many other things we take for granted were un-heard of 15-20 yrs ago.

It's hard to appreciate how reccent %90 of what we know and do in this hobby really is. I have some Marine fish magizines from around 1990, they are good for a good laugh. Massive wet drys, "reef tanks" with almost nothing but calupera as tank of the month, no concept of captive propogation........

The reef hobby is in it's infancy more or less. Wet dry filtration was the thing when we saw the hobby as being as simple as the basic nitrogen cycle. Now it's understood that there are a whole lot more things going on in a reef tank.

Beware of older books and stores that aren't into modern reefing, beware of all the newest trends (because they are not time tested), and beware of every established "fact", since that may too change in 5 yrs :) . Think the hobby in general as one big dynamic learning and exploration process that goes on and on.........

[wsonner]

Wet dry filtration originated before there even was LR in the hobby. The wet dry approach actually, IIRC, came from sewage treatment.

As far as I know of the first person to begin to play with LR was Lee Chin Eng in Indonesia around 1960, but he was pretty much filling a buckett from the real reef and walking home and placing the rock in his tank. Commercial rock didn't come around until way later.

The hobby has advanced progressively since then.

Wet dry filtration was really revolutionarly for the hobby when people were only keeping fish and coral skeletons, systems with massive fish waste, virtually no biodiversity, and no concern with nitrate. Skimmers began to pop up around the same time, but they were nothing compared to what we have now.

Ca reactors, MH lighting outside of pee yellow industrial bulbs, Acropora living in captivity, and many other things we take for granted were un-heard of 15-20 yrs ago.

It's hard to appreciate how reccent %90 of what we know and do in this hobby really is. I have some Marine fish magizines from around 1990, they are good for a good laugh. Massive wet drys, "reef tanks" with almost nothing but calupera as tank of the month, no concept of captive propogation........

The reef hobby is in it's infancy more or less. Wet dry filtration was the thing when we saw the hobby as being as simple as the basic nitrogen cycle. Now it's understood that there are a whole lot more things going on in a reef tank.

Beware of older books and stores that aren't into modern reefing, beware of all the newest trends (because they are not time tested), and beware of every established "fact", since that may too change in 5 yrs :) . Think the hobby in general as one big dynamic learning and exploration process that goes on and on.........

Amazing what a little context will do for you. Thanks so much for your very insightful post. I started in 1993 with a 55 gallon show tank, black and green dolomite over an under gravel filter, carbon cartridges on the uptake tubes which were pushed by airlines and bubble stones. I had a 16" orbicular bat fish (named Wally :-) and a heater. I guess I really have "grown up" in parallel with the hobby's growth and that's why certain things seem like they have always been around because for me they have been. When I got "advanced" enough for wet-dry it was there, live rock, it was there. When I got "advanced" enough for decent lighting it was there etc etc. So now, in my mind, certain things like coral propagation and protein skimmers have always been there. And it never dawned on me that wet-dry was for fish only tanks but now you've helped me make that connection and answered my question about why it would be considered a "nitrate factory"...because the term was coined in the context of reef keeping where nitrate plays a much bigger role in our success than it used to. And a lot of our focus has shifted from de-nitrification methods to nutrient export mechanisms which alleviate some of the need for old time "nitrate factories". Thanks. Now I can sleep at night and stop doing equations and graphs in my HEAD! Where's my Zoloft?

[marco67]

Ya know it's funny in a way reading the transition of this post.

Never mind what the last 5 years has brought us. Imagine the next 5 and the next after that. I've tried to make it habit to never talk in absolutes because if nothing else I've learned there are none.
What will we consider obsolete next year, in 5 in 10 and when will they change from controversy to fact?
I've said this before and it's no revelation but Metal Halides! Bye! SeYa! Won't miss ya! got my elect bill today and I'd like to take a hammer to ya!!!

My RC sig since the day I logged on Nov 2000.
"The more you think you know, the more you need to learn"

Then it was about a newbie sorting out all the anecdotal "truths", the meaning has changed over the years but I think it will be my motto/ mantra forever.

RE the Nitrates nice one John

Sorry for the digress

[wsonner]

...

"The more you think you know, the more you need to learn"

...



And once again...life imitates art :-).

[shawn]

LockeOak, I agree with your explanation. It isn't that bio-balls, etc..., are too good at the job they do, it's that they can't do the whole job. One needs a well rounded filtration system - not one that leaves off the last step.

[jimmyj7090]

"RE the Nitrates nice one John

Sorry for the digress"


Hehe, I was about to post again and appologize for my rant (is that what people call a "blog" :( ).

I've only been in this since about 95, but between the way I learned things in the first place, and from reading old books and magizines, I find it pretty amazing to see where we are at now.

I guess FWIW a little reefing historical context is an often overlooked and undermentioned topic. People jump all over new reefers for buying a canister filter or wet dry, yet those were the right things to get not so long ago.

For anyone reading this/wondering/curious, I'd highly reccomend picking up a copy of Delbeek and sprung's "The Reef Aquarium vol 3' for some great current reading that also covers some very relevant reefing history. Fantastic and wide ranging book that was just published. (One of the things that used to confuse me the most was reading books without taking the publishing date into consideration).

[~Flighty~]

The biggest aspect of the nitrate factory is that it works against the skimmer. Wether it is a sponge or a wet/dry etc it holds onto the waste and excess food and breaks it down into something the skimmer can't get out of the water.

[shawn]

The biggest aspect of the nitrate factory is that it works against the skimmer. Wether it is a sponge or a wet/dry etc it holds onto the waste and excess food and breaks it down into something the skimmer can't get out of the water.

Is this true? I thought that skimmers removed dissolved substances by "sticking" them to the air/water surface of the multitude of bubbles. Such dissolved substances wouldn't be trapped by physical media, would they? I thought the the purpose of such media was to provide a large surface area for bacteria. Such media may trap particulates, but that isn't really the purpose of a skimmer, is it?

[jimmyj7090]

Yes that is right.

Skimmers remove dissolved nutrients as you described, but they also pull out plenty of not-so-dissolved crud.

By not having a wet dry or filter foam much of the detritis and other solid waste stays suspended in the water and ends up getting caught in the skimmer foam and is removed before being broken down.

Nitrate is dissolved nutrients, but skimmers don't do much to remove nitrate directly, they remove it by pulling out crud before it is broken down into nitrate. Hence the advantage of not having a wet dry or mech filtration. This is also why it's commonly reccomended to change out carbon very often if it's used in a reef tank - because if it's not changed out regularly it will become a mechanical filter as well as a chemical filter - holding solid waste without removing it.

[wsonner]

Is this true? I thought that skimmers removed dissolved substances by "sticking" them to the air/water surface of the multitude of bubbles. Such dissolved substances wouldn't be trapped by physical media, would they? I thought the the purpose of such media was to provide a large surface area for bacteria. Such media may trap particulates, but that isn't really the purpose of a skimmer, is it?

They both remove dissolved "organics". One by foam fractioning and one through bacteria. I think Flighty's point is right on in that the more efficient biological filters will convert dissolved organics so fast that the skimmer doesn't have time to remove them by foam fractioning and that once the filter converts it all to nitrate the skimmer can't help you. The idea is to remove these dissolved organics with the skimmer before the bio filter gets to them to help keep nitrate levels down because reef inverts and corals are much more sensitive to nitrate than fish in the old style fish only tanks where biological filtration was sufficient.

[shawn]

Thanks for the explanations!