Media in dry sump area?

[Ping]

I am installing a new sump tonight. It came with ceramic media to put in the trickle (dry filter) section. The media is on a shelf/ basket in the tower, below the filter pad . The water from the display will only trickle through this. The media is not submerged. I am thinking of removing the media to lower or prevent an increase in nitrates, nitrites. Looking for opinions. Am I correct?

[GaryP]

Filter media causing an increase in nitrates levels is the reefer version of an old wives tale. Nitrates are part of the nitrogen cycle. What causes an incerase in nitrates is a lack of biological activity to convert nitrates to nitrogen gas.

[StephenA]

Gary;

Shouldn't you clean the media in these type filters about every 3-4 months?

I'm about to add one of these to my Puffer's tank.

[Polkster13]

You shouldn't need to clean the ceramic media. If you do, you will kill off part of your biological filter. I have never cleaned mine. You should have a foam filter below to ceramic media to "polish" the water. The foam filter should be cleaned usually monthly depending on bioload (and the amount of gunk being deposited on the foam). If it is getting clogged before the month is up, you will need to clean it more often.

[StephenA]

What's best, bio balls or ceramic?

[GaryP]

Stephen,

Talk to DoninSA about the cubes he has been using. He got them from FA. I think he has been very pleased with them on his aggressive reef. In addition to the aerobic cycling that you get from most media, I think he has seen some nitrate reduction as well. The center of the cube supposedly is anoxic like in a DSB. I would recommend a floss filter before the media to prevent detritus from getting into the media in the first place.

[Polkster13]

You want lots of surface area for the nitrifying bacteria to live on. The more surface area the better. A lot of the ceramic is very porous. The bio balls have a lot of surface area and are much lighter. I use ceramic in my Eheim canister filter and biocubes in my DAS filter (it is easier to get them out so I can do maintenance to the internal pump).

As far as which is better, I think it is more of a personal choice. I like both. As long as weight is not an issue, get which ever will fit the best in your filter.

[don-n-sa]

Yeah.."the best" is debatable. As for cleaning bio-media...just rinse them with water from your tank during a water change,that way you wont kill any bacteria. I have removed the bioballs from the right tower DRY area of my filter because I subscribe to the theory that that's where the main source of nitrates are created and not converted to nitrogen gas. Currently in my filter I am using a few different methods of biological filtration...keep in mind that I have a dual tower wet dry. On the left tower I have filter floss (change weekly), then bio-balls mixed with chem stars, then in the submerged part I am trying out the Cell pore block. On the right tower I have filter floss again then currently nothing in the dry part then in the submurged area I have filled it with rock rubble. There happens to be HUGE populations of mysids and pods in the rubble. I also recently put two large pieces of dry pukani in my sump area. My goal is to have my 240g aggressive reef to have nitrates at zero or as close to it as possible. 2 months ago nitrates were at 40+ppm...two weeks ago they were at 20ppm. I have not tested since the removal of the bio-balls from the right tower.

[GaryP]

IMO, any nitrate level has nothing to do with the presence of bioballs or other media. It does has to do wuithe the lack of adequate environment for bacteria (Nitrobacter) that do the detrification (ntratye to nitrogen) step of the nitrogen cycle.

[don-n-sa]

hmm...you do agree that they do their job well though right...I mean that they convert waste and uneaten food in to nitrates correct? But are bio-balls in the drip area capable of converting the nitrates that are produced into nitrogen gas?

[Polkster13]

Here is a good link (http://www.physicalgeography.net/fundamentals/9s.html) describing the nitrogen cycle in detail. To answer your specific question:

Denitrification is also common in anaerobic areas and is carried out by heterotrophic bacteria.

This means you need an area with little to no oxygen. This occurs deep inside porus LR, a plenum or under DSB's. I am not sure if you could replicate this type of environment inside a wet/dry filter.

[don-n-sa]

I agree with you Polkster , that is why I question Gary's comment on bioballs not being a source of nitrates. If they do their job , in which I believe they do, the end result is nitrates because bio-balls especially in the oxygen rich drip area in the wet-dry do not complete the cycle...which is dinitrification.

[GaryP]

The whole purpose of a wet dry is to produce a highly oxygenated area that maximizes the earlier steps of the nitrogen cycle. Bioballs do this very well. The problem is that when they get through with these steps the product is nitrate and it needs a different type of bacteria to complete the process. The cycle is often broken at this step and the result is a build-up in nitrates that are basically stacking up because of a lack of bacteria to process it. Its like freight stacking up on a dock because there aren't enough forklifts to move it. In this case, the forklifts are the bacteria that live in the anoxic areas. They can not live in highly oxygenated area like bioballs. The theory of the Cell-pore that you are using is that the aerobic bacteria that live on the outer surfaces use up the oxygen before it reaches bacteria that live in the center of the brick and thus creating an anoxic zone. That's basically the same thing that happens with LR and a DSB.

The aerobic bacteria have a much faster metabolic rate than the anoxic bacteria. I think that's the problem with some systems. Everything is designed to maximize aerobic digestion of waste with little consideration for the requirements for anoxic processes. I think this is a leftover from FW and FO system designs where nitrates are a farily small concern. Do not misunderstand what I am saying. The aerobic processes are very important. The problem is not in what they are doing, the problem is what doesn't happen after they have done their job. Saying that you are going to reduce nitrates by cutting back on aerobic metabolism is like saying you are going to cut back on your trash disposal by not taking the trash to the curb. It still piles up, but just in another form. The bad part is that the other form (like nitrites and ammonia) is worse than the stuff on the curb (nitrates).

[don-n-sa]

anyway here are some pics of my wet dry...I can feel the nitrates lowering as we speak 8)

[don-n-sa]

that was the right side...here is the left

[StephenA]

I can feel the nitrates lowering as we speak


:LOL

I like how the nitrate test kit is in the first pic

[don-n-sa]

Gary, that was an excellent explanation...can you go into more detail please...that was way to short and to the point.... :lol I will be adding more cell pore to the right side and to the left drip area. Hopefully I will reach my goal of near zero nitrates, so when I ugrade my lights I can do A, notice I emphasize only one, colony of SPS. I want to have a successful agressive fish reef with a few softies, LPS and and a cool large SPS colony. This is something that I have not seen done successfully done long term.

[GaryP]

I think we need to work on a microbiology talk after we do the chemistry talk.

[don-n-sa]

uhh...why do you say that?

[StephenA]

I think we need to work on a microbiology talk after we do the chemistry talk.

Agreed!

[Ping]

Alot to digest. Is Rubble deep enough to have anaerobic bacteria. I remember the post on cell-pore. Don, how long have you had yours in the sump. Any idea how long before is "seeds" with benificial bacteria.

Oh, and thank you all for the info. I enjoy reading the thought provoking debates.

[don-n-sa]

Ping...its been a few months now. I can't say for sure on how long it takes the cell-pore to colonize, maybe Gary can help with that. One thing is certain...my nitrates are on a slow decline, the problem is that I am doing so many different things I am not sure which one is working the best.