"Nitrate Factory" - What's the big deal?

[neilanh]

I hear lots of you talk about "nitrate factories" when referring to the use of canister filters, wet/dry setups, bio-media in general. I don't understand this, can someone explain it? Don't get me wrong, I understand why it's important to maintain low levels of nitrates in a SW aquarium, that's not what I want to discuss.

I think I understand the concept. These types of setups allow for a great area for nitrifying bacteria to grow - high surface area, higher flow rates, lots of times highly oxygenated areas - which the bacteria thrive in. This is the concept we use in FW systems, and for those systems it's preferred.

Why the difference in SW setups? Essentially, saltwater tanks undergo the same nitrogen cycle as FW setups. You need these bacteria to convert waste (leftover food and fish waste, etc) through the cycle and to the end product of nitrAte anyway, whether FW or SW. Then you use other means to clean out the nitrAtes - plants, macro algaes, PWCs, etc.

If you create these "factories" in SW tanks, it's no different in my mind than allowing the bacteria to grow in the tank on the LR, BR, substrate, etc etc. Either way, the bacteria are going to grow in the tank and do their job of converting waste through the cycle. So why then, does it matter, if the bacteria live in a canister filter, wet/dry system, or on the LR and substrate in the tank. I can't figure out the difference. The size of the bacteria colony is going to be dependant on how much waste is being produced by the tank, why does it matter where they live?

Having these factories aren't going to produce more nitrAtes. The amount of nitrAtes produced is directly proportional to the amount of waste in the tank. The only thing I can figure is that these areas provide a place for gunk to build up and rot, creating more waste in a centralized location. But, that waste exists in the tanks whether or not it collects on a filter pad or not - so I'm still confused.

Someone teach me the ways of the "dark side" - as you like to call it.

 

[fijiwigi]

I totally agree with you. Very thought out explanation neilanh.
I think the main reason is that filters trap waste and are exposed to air? And in Saltwater there is not really a need for them because the live rock does the jobof housing the bacteria and the live rock is fully submersed in the water... Maybe the oxygen helps the Nitrates to grow faster on any filter pad or live rubble or bioballs that are exposed to air and not fully submerged. Granted my overflow box has a foam pad that is exposed to air and traps waste. I don't have the answer I am just kinda thinking outloud. Bottom line is just monitor your parameters and if you don't see your filter causing a problem than its not a problem,.

 

[Kurt_Nelson]

"Nitrate factories" is probably a bad term, because as you said... that's what we want, right?!

The thought process goes along the lines of what fijiwigi said... if you have enough live rock, you have more than enough area for bacteria to populate. Therefore, the cannister filters and biowheels aren't necessary for the purpose of housing nitrifying bacteria. The wet/dry type filters are very VERY efficient at converting things to nitrates. And for that reason, anything that gets trapped in them that will turn into nitrates will do so very quickly. Those "trapped nitrates" are "extra", if you think about it. If you didn't have that cannister/biowheel that trapped the stuff to start with, you wouldn't have those nitrates. And in a reef, nitrates are a thing you want to keep as close to zero as possible. For that reason, I think they've unfairly got the negative name of "nitrate factories."

I'm of the opinion that if PROPERLY MAINTAINED, cannisters and biowheels can serve a purpose in SW. Cannisters are great for additional volume, a place for more live rock, or to run chemical media. Biowheels are great for maintaining a "seeded" biological media that can be switched over to a quarantine tank on a moments notice. I use a Biowheel 100 on my 46g tank for that very reason, and I've used it once to set up a 10g QT in 15 minutes, cycled and ready to go. My nitrates right now are 1.0ppm... worst they've been is pushing 2ppm.

But you have to keep the sponges clean - cleaning them at least weekly - otherwise you're going to end up with higher nitrates than without the unit.

 

[melosu58]

Chemistry and the Aquarium

Aquarium Frontiers Library

Read these. As far as why I think Figi hit it as those other things they can trap waste While if you use LR the waste is caught up in the water column and easier for the nitrifying bacteria to get to. I had a wet dry for several yrs and I was always having nitrate problems. Sometimes as high as 80 or 90. With just LR and a skimmer and a fuge it pretty well stays at 0. I know it`s not a great explanation. I had some great articles on biological filtration that I recently lost when my hard drive crashed.

 

[neilanh]

Thanks for the thoughts, and I'll take a read through your links melosu, thank you.

I understand what you're all saying, about canisters and wet/dry systems trapping stuff and converting it quickly to nitrate. But, it's not trapping anything that isn't already there, so in essence all the stuff it's trapping and converting exists and will be converted over time regardless of where that occurs - in a canister or in with the LR.

I wasn't arguing the necessity for it or not. I understand that a SW tank with adequate live rock and sand will harbor more than enough bacteria to do all the work we need with our tanks on their own. No questions there. My only point was that in general canisters and these other types of systems appear to be frowned upon in the hobby. I understand they're not necessary for a system of adequate stocking of LR and sand, but again, in essence they do the same thing, and they don't add nitrates that won't be there anyway.

An aquarium is going to generate a certain amount of waste, based on stocking and feeding habits of the owner. Having a canister filter or wet/dry, etc, doesn't have any way to make the end result, nitrates, any worse than not having one of these systems does.

This is my hypothetical point. If you had 2 completely 100% identical systems (not possible, i know, hence the hypothetical comment), the only difference being that one of the systems had wet/dry system on it. They will both run the same end result, an identical amount of nitrate. This is based on the fact that nitrate is directly proportional to the amount of waste generated in a system. A wet/dry or canister doesn't produce extra nitrate or even extra waste. It's just another place for the bacteria to thrive.

So I must be missing it, because I just do not see how having one of these systems in place can cause the nitrates in a tank to be any higher. Waste is waste, bacteria convert whatever waste they have to nitrates. The size of the bacteria colony is directly related to the bioload of the waste that's generated. There's no way for these systems to produce extra nitrates that wouldn't exist anyway.

What am I missing?

 

[Innovator]

Thanks for the thoughts, and I'll take a read through your links melosu, thank you.

I understand what you're all saying, about canisters and wet/dry systems trapping stuff and converting it quickly to nitrate. But, it's not trapping anything that isn't already there, so in essence all the stuff it's trapping and converting exists and will be converted over time regardless of where that occurs - in a canister or in with the LR.

As you know, a very basic nitrification model is as follows: NH3 -> NO2 -> NO3. Bacteria species coated along the surfaces within the aquarium and even live organisms quickly oxidize Ammonia (produced by organisms consuming organic matter) to Nitrite and Nitrite to Nitrate; Thus, consumption = production. Nitrate; however, is denitrified by bacterias within live rock and deep sand beds to eventual N2 gas and dispersed into the atmosphere. Bioballs cannot not achieve the anaerobic conditions required to denitrify and the nitrate populations continually accumulate in the water column, negating the live rock and deep sand beds of their further duties.

I wasn't arguing the necessity for it or not. I understand that a SW tank with adequate live rock and sand will harbor more than enough bacteria to do all the work we need with our tanks on their own. No questions there. My only point was that in general canisters and these other types of systems appear to be frowned upon in the hobby. I understand they're not necessary for a system of adequate stocking of LR and sand, but again, in essence they do the same thing, and they don't add nitrates that won't be there anyway.

Well, yes and no. Although the numerous surfaces do house bacteria, we as aquarists are constantly introducing nitrogen into the system via food in addition to other sources and eventual waste acts as a catalyst to build up nutrient loads. Although these wastes are eventually broken down, the rapid influx can overload particular bacterias until they can repopulate enough to handle the increase.

An aquarium is going to generate a certain amount of waste, based on stocking and feeding habits of the owner. Having a canister filter or wet/dry, etc, doesn't have any way to make the end result, nitrates, any worse than not having one of these systems does.

If you do not have adequate export then there is no reason as to why No3 wouldn't continue to rise and since canister filters and bioballs cannot provide such biological control it can become a problem.

This is my hypothetical point. If you had 2 completely 100% identical systems (not possible, i know, hence the hypothetical comment), the only difference being that one of the systems had wet/dry system on it. They will both run the same end result, an identical amount of nitrate. This is based on the fact that nitrate is directly proportional to the amount of waste generated in a system. A wet/dry or canister doesn't produce extra nitrate or even extra waste. It's just another place for the bacteria to thrive.

See previous responses in this post.

So I must be missing it, because I just do not see how having one of these systems in place can cause the nitrates in a tank to be any higher. Waste is waste, bacteria convert whatever waste they have to nitrates. The size of the bacteria colony is directly related to the bioload of the waste that's generated. There's no way for these systems to produce extra nitrates that wouldn't exist anyway.

What am I missing?

Nitrate isn't necessarily decreased in production when such a device is removed, but rather it is vanquished to other areas for diffusion. So, is such media worthless? My personal experience leads me to believe absolutely not and of course, depending on what your desired outcome is. NO2 and NO3 have very little effect on marine fish and soft corals, but other invertebrates may decrease in overall health if accumulated in large quantities.

 

[melosu58]

Very good explanation James.

 

[Ziggy953]

I'm impressed!
Regardless of which way you want to go with your system there are people our there that have done it and been successful with it. So, what you decide to do with your system is a personal choice, it is proven that canisters, HOB, wet/dry and tons of other filtration systems work and support beautiful, healthy successful systems. My personal choice is to mimic nature as best I can. I like using as natural a method as I can thus my large refugium and lots of LR. People say that a skimmer isn't natural. Maybe it isn't but it mimics nature. Ever been to the beach and watched a wave crash on the sand and the foam stay behind as the water recedes? Looks pretty nasty right? Natures skimmer. The point is you have to take what you know and learn and apply it to your system the way you feel it is going to work best for you and the animals you are going to keep. If you want to use canisters or wet/dry filters then go for it! They are proven methods. You are right in your thinking waste is waste and the filter doesn't create that waste. I personally don't like canisters or HOBs, too much maintenance for me. There isn't a single sponge on my system.

 

[neilanh]

Great explanation James, thank you. I'm still not fully convinced, mind you, but i'm starting to see the big picture - maybe.

Actually I have no plans to run one of these myself, I just keep seeing the term "nitrate factory" come up and had to ask about it. lol

 

[Innovator]

I hope it did bring some insight to some of your queries. I am not trying to convince you one way or the other mind you, as the term does imply that such "nitrate factories" sustains a negative impact on aquaria, which simply is not the case. I have stated in other posts that I do not know of a single public or commercial venue that does not use such media as a major component; nonetheless, biological filtration along with proper export can suffice in keeping a natural ecosystem functioning. If you have any other questions, feel free to post them

 

[cmor1701d]

James' explanation tells the story. The wet/dry or cannister filter do not aid in the last part of the nitrogen cycle; nitrate to nitrogen. LR does to a certain extent and so does a DSB. Macro algae also aids in that regard.
If you have enouhg LR (1½-2 pounds/gallon) you do not need a cannister or wet/dry for biological filtration. The LR will not only convert ammnia to nitrite and nitrite to nitrate, it will also help convert some nitrate to nitrogen. In combination with a dsb the effect can be enormous.

So the wet/dry or cannister is not really a nitrate factory so much as it is only 2/3 of the factory needed to complete the nitrogen cycle. Well maybe it is a nitrate factory then