# HELP: Specific Water Chemistry/Cycling Question



## ncutler (Apr 26, 2010)

I was an LFS today and in discussing Bio Media, I my knowledge and the owner's knowledge didn't seem to match.

Owner's position: Biomedia (with a focus on ceramic rings as we both used as an example) is for reducing Nitrates. It allows both aerobic and anaerobic bacteria to colonize the surface, but increasing biomedia is for the purpose of increasing area for anaerobic bacteria to colonize thus removing *Nitrates*.

My position: Biomedia is primarily for the cycling process that converts Ammonia to Nitrites then Nitrites to Nitrates, where it *does not* reduce Nitrates. Specialty media must be used for that purpose where the surface area has aerobic bacteria colonize which allows for the deeper areas to develop anaerobic bacteria. Therefore low flow is required to produce such environments so Canister filters loaded with bio-media would increase the aerobic bacteria but would have negligable effects on anaerobic bacteria since the flow would be too fast.

We both felt that our positions were correct, but they seem to be at odds with each others position. I should state that his theory comes from a saltwater perspective, but he felt that it would not matter.

Does aerobic and anaerobic bacteria colonize the same surface?
Does aerobic bacteria compete with anaerobic bacteria for space?

Could there be a difference in the cycling process between freshwater and saltwater that could explain the difference in the two above perspectives?

Questions I thought I understood, but maybe I don't. Any help would be appreciated in your knowledge of water chemistry and the cycling process.


----------



## ngo911 (May 19, 2010)

I would agree with you. Anaerobic bacteria cannot colonize on the surface of regular biomedia because there is oxygen there.

Basically what you have stated is what Seachem's denitrate states. Seachem. denitrate


----------



## flannel (Apr 21, 2010)

Yeah, you're on the money. As far as I've ever learned the only way to get nitrates out of the system is with plants and water changes. I think your LFS guy is making the very common error of confusing nitrItes with nitrAtes. It's so hard to wrap your head around that in the beginning and very often it just never 'clicks' with some people. And you're also right, aerobic bacteria need oxygen to thrive. Anaerobic bacteria don't survive with lots oxygen. I don't know about the proportions in different filter designs, so I'll be watching this thread to learn about that. It is all very science-y and lots of people just can't cope with it, but it seems to me that you pretty much understand it the same as I do  Of course, I still have a ton to learn and not much brain space to store it in lol, so I look forward to learning more here.


----------



## darb (Apr 21, 2010)

There is a newer product on the market for salt water systems called biopellets. One of there makers claims that both anaerobic and aerobic bacteria inhabit the media. So I suppose that it is possible that the outer aerobic bacteria creates an anaerobic environment within the outer sphere of the media.

Nitrate consuming bacteria are commonly used in SW aquariums, commonly in deep sand beds and live rock and sometimes reactors and now biopellets. I have been planning on trying out the DSB and live rock method in fresh water tanks, but I need a triple stacker for that so that I can try the above two methods and maintain a third control tank.


----------



## ncutler (Apr 26, 2010)

The odd thing is, This guy really knows his stuff. He's the one I go to for any very specific information. Taught me the concepts of why Ammonia will increase when you let fish out of the bag into an aquarium (Ammonium converting quickly into Ammonia because of the shift in Ph level). Told me specifics of how methalene blue works etc. That's why it's blowing my mind with this - I keep thinking I must have misunderstood him, but he was clear about both aerobic and anaerobic bacteria competing because they use the same surface, which to me defies what ceramic rings are designed for.

I've built a coil denitrator specifically because of trying to reduce nitrates in FW. I've also got bags of seachem de*Nitrate and Kent Nitate Sponge in my cichlid tanks and all my research defies that.

I'm actually looking at getting the biopellets, because they say they work even in FW. It seems like having carbon available to the anaerobic bacteria is important. I will look more into the biopellet, because my understanding is that aerobic always colonizes the surface while anaerobic then colonize the interior. Perhaps this is not the way biopellets work.


----------



## darb (Apr 21, 2010)

ncutler said:


> I'm actually looking at getting the biopellets, because they say they work even in FW. It seems like having carbon available to the anaerobic bacteria is important. I will look more into the biopellet, because my understanding is that aerobic always colonizes the surface while anaerobic then colonize the interior. Perhaps this is not the way biopellets work.


I was considering trying them in FW also, but I hate doing water tests ....

If you do try them, be sure and start a thread on it. They are on sale at J and L right now also.


----------



## ncutler (Apr 26, 2010)

darb said:


> They are on sale at J and L right now also.


That's how I found out about them! 

I'm currently using my DIY coil denitrator that worked extremely well at reducing my nitrates before. But I did both coil denitrator + seachem de*nitrate at the same time, so decided to not connect my coil denitrator after 10G of water spilled out on my floor when the tubing came off my pump. Now that my Nitrates are arising again, I figure I'll try the denitrator to see how effective it is. If it still struggles, then I'll try the biopellets so I can workout what works and what doesn't work.

All this research and work makes me think that it's not as simple as just adding general bio media (like ceramic rings) to reduce nitrates.


----------



## davej (Apr 28, 2010)

I think it sounds like he is comparing live rock for saltwater. It has bacteria growing deep inside the rock in anaerobic conditions. These bacteria break down nitrate if my memory serves me correct. It is the same principal with the saltwater deep sand bed principal. With that you created a void under your sand. Much like having a under-gravel filter plate at the bottom of the tank but with no uplift tubes just buried under the sand. In this void anaerobic conditions occurred, again with the result of the bacteria using up nitrates. 
I'm no expert but I don't think the ceramic rings would be big enough to provide the anaerobic conditions deep inside needed to de-nitrate.

As for a coil denitrator, if you can get it to work all the power to you!
In my attempts way back when, I never had any luck getting my flow set just right. It has to be very slow and mine seemed to get clogged all the time screwing up the flow.
Bigger pain than a simple water change now and then, in my opinion

As for bio-pellets might be worth doing some research on them, they seem to be primarily used in saltwater. Not sure if it is a chemistry thing with the more alkaline water or what. Let us know what you find it would be very interesting. I would think that if they were that effective with fresh water they would be heavily marketed to the freshwater enthusiasts. I'll bet there is a heck of a lot more freshwater tanks compared to saltwater out there.


----------



## ncutler (Apr 26, 2010)

davej said:


> As for a coil denitrator, if you can get it to work all the power to you!
> In my attempts way back when, I never had any luck getting my flow set just right. It has to be very slow and mine seemed to get clogged all the time screwing up the flow.
> Bigger pain than a simple water change now and then, in my opinion


Currently I'm getting a lot of ammonia and nitrites still. I suspect it's from the leftover bacteria dying in the water from when I stopped using it (it was not being used for 4 months). I noticed that it clogged a fair amount as well when I last used it. Weird how it works fine at first and then slowly decreased drips per second over time. I've made sure both times to have a good prefilter so no particles can get in. We'll see how the second time goes.



> As for bio-pellets might be worth doing some research on them, they seem to be primarily used in saltwater. Not sure if it is a chemistry thing with the more alkaline water or what. Let us know what you find it would be very interesting. I would think that if they were that effective with fresh water they would be heavily marketed to the freshwater enthusiasts. I'll bet there is a heck of a lot more freshwater tanks compared to saltwater out there.


I also notice how few people know of seachem's de*nitrate and kent's nitrate sponge. I suspect that in freshwater, few people really care about nitrates because livestock generally is more tolerant to it. Not to mention water changes are usually easy enough to do to maintain low enough nitrate levels.


----------



## MadgicBug (Apr 22, 2010)

ncuttle you are correct. Davej is correct about the live rock.

Some people use lava rocks and IMO they are like live rocks for FW tanks.

I think the catch is that the denitrication process can not keep up unless you have lots as that is why it is recommend to put in 1 to 2 lb of live rocks per gal (can't remeber the exact number). That is why WC is the best way.

I had some nitrate sponge left over from my SW supplies. I figure I would put it to my FW tank to drop the nitrate to 0 to reduce some algae issue. Well it dropped it to 0, but created other problems with my plants.


----------



## ncutler (Apr 26, 2010)

MadgicBug said:


> I had some nitrate sponge left over from my SW supplies. I figure I would put it to my FW tank to drop the nitrate to 0 to reduce some algae issue. Well it dropped it to 0, but created other problems with my plants.


I did notice two tanks at my office had completely different Ph levels. One had 6.4, the other 7.2. The only difference was one had nitrate sponge in it. Made me think it might change ph. What was your problem?

I also have some lavarock in my 20G with the coil denitrator. Wouldn't dead rock also work if it's works for SW? Then again, most people don't want to loose the extra room for water.


----------



## MadgicBug (Apr 22, 2010)

The problems was that I had nutrient imbalance....some plants started to no look that nice. created a different kind of algae problem as the plants couldn't use up other nutrients such as phospate, etc. Anyhow I stopped that and left my nitrate at around 20ppm. My plants, fish and shrimp are fine with it and are really heathy.

As for LR in a FW tank. A lot of LR will alter your PH and drive it up and slowly disolve away. Not enough LR will be next to useless, but good for a little buffering. Hence lots of lava rocks. I don't use any lava rocks and rely on plants, WC and control my feeding (even when they beg for more)

I have an over flow where I keep filter media which I change\clean twice a week (2min each change) i.e. remove the source regularly.


----------



## MadgicBug (Apr 22, 2010)

ncutler said:


> I did notice two tanks at my office had completely different Ph levels. One had 6.4, the other 7.2. The only difference was one had nitrate sponge in it. Made me think it might change ph. What was your problem?


That should not be the case as marine tanks runs at PH 8+ and this would cause havoc. PH 6.4 (during day time I assume) tells me its a buffering issue. Take a KH reading on that tank and its probably 0 to 1. I assume you are not doing CO2. Even if you have using ADA it would drops to around 6.8. The Nitrification process produces nitrate acid, which uses up KH (buffering) in your water. Once you buffering goes down your PH drops.

Add some buffering such as equilirium...I wouldn't do baking power unless you really know what you are doing as it can spike the PH up and cause more problems.


----------



## darb (Apr 21, 2010)

If you followed my link in my fist post you would have seen this graphic:










with the inner circle supposedly being a biopellet (a dense, small diameter media), an aerobic layer of bacteria and an inner layer of anaerobic bacteria in a recommended high flow environment. Thus the claim is that BPs reduce nitrates by providing the added nutrients from the BPs and an environment for the bacteria to grow.

I am a long way from being a microbiologist, or any type of biologist for that matter, but this does contradict all that I understood about anaerobic bacteria. But I will assume that they (manufacturers of BPs) have worked closely with a microbiologist at some point, and that their diagram is workable.

So in a nutshell, this supports the "owner" in your first post.

Few additional points:

be careful if you coil goes bad, I have read about a person that cut open his coil in the living room and it ended up killing his dog, family had to run out of the house and the fire department came. H2S is deadly in relatively low concentrations.

lava rock is no where near as porous as reef rock, pumice floats because it is closed cell, the water still slowly flows slowly through reef rock, all be it very slowly.


----------



## ncutler (Apr 26, 2010)

Interesting, though from the diagram, it still seems to be on difference surfaces to me, that the outer is aerobic and inner anaerobic. I'm having a hard time understanding the diagram if this isn't the case.

I would imagine the danger of the H2S was from an amount being suddenly released. I'm aware of always monitoring the smell. Right now, as I said, there's no drop in nitrates from it, so there's something aerobic going on (ammonia + nitrites). But thanks for the warning!

On a side note: I was very creeped out when the dentist described the functions of aerobic versus anaerobic bacteria in our mouth - it parallel's aquaria closer than I ever thought.


----------



## MadgicBug (Apr 22, 2010)

I guess they went high tech with his stuff and probably designed it for high water flow.


----------

