Anaerobic Zone question

[Cornerboy]

Hi guys!!

I was wondering about trying to create an anaerobic zone in the bottom half of my filter sock chamber. I hate to see the space wasted.

I have a 55 gal DT and a 55 gal fuge/sump. The first compartment is 4-5" x 12" x 18". What I was thinking was to take four or five filter media bags of loose pukani rubble and Marine pure and stack them like a layer cake with loosely fitting sheets of acrylic in between them just to reduce the flow in the bottom half of that chamber. I was thinking I could run an airline down there so I could micro dose carbon to the anaerobic zone. Would this be a feasible idea and a worth wild use of that space???

The next chamber is the skimmer chamber and I eventually plan on running ozone through the skimmer with a bag of carbon in a high flow area there. This is for a mixed lps/softie tank that will have 3" of sand in the DT, fyi.

Thoughts? And thanks for sharing your wisdom!!!

 

[Randy Holmes-Farley]

Why?

Anaerobic would be bad, potentially producing toxic hydrogen sulfide.

Nitrate is not had to control, if that is the purpose, and some media like the Marine pure alone can accomplish it (although I not a fan of such media).

 

[Cornerboy]

Why?

Anaerobic would be bad, potentially producing toxic hydrogen sulfide.

Nitrate is not had to control, if that is the purpose, and some media like the Marine pure alone can accomplish it (although I not a fan of such media).

Yes that would be the purpose. To control nitrate and reduce any need for water changes or other methods. I was going to put Marine pure down there. I'm curious why you are not a fan of marine Pure or anaerobic zones. As well as your primary methods of managing nitrate.

I guess aside from nitrate management the other thing is it just seems like three or four gallons of wasted water space below the filter sock.

Thanks Randy!!

 

[Cornerboy]

Why?

Anaerobic would be bad, potentially producing toxic hydrogen sulfide.

Nitrate is not had to control, if that is the purpose, and some media like the Marine pure alone can accomplish it (although I not a fan of such media).

Also I didn't think hydrogen sulfide would a problem if you're tanks oxygenated. That's part of why I thought right before the skimmer, particularly if I am going to run ozone like I plan, would be an ideal spot. Educate me dr. Randy!!

 

[Randy Holmes-Farley]

Yes that would be the purpose. To control nitrate and reduce any need for water changes or other methods. I was going to put Marine pure down there. I'm curious why you are not a fan of marine Pure or anaerobic zones. As well as your primary methods of managing nitrate.

I guess aside from nitrate management the other thing is it just seems like three or four gallons of wasted water space below the filter sock.

Thanks Randy!!

IMO, nitrate is not the reason to do water changes. There are many other things it accomplishes.

Anaerobic is very bad in seawater. Luckily, it is not common, but adding organic carbon into a trapped space would do it. Dosing of organic carbon into an essentially closed space would do it. Hydrogen sulfide is produced, which is very toxic. The term you want is hypoxic, meaning less oxygen than aerobic but more than anaerobic. In particular, there is a series of chemical species that organisms use to help metabolize organic carbon. In a reef environment, first is oxygen, second is nitrate, and third is sulfate. If you consume all the nitrate and sill have organics present, that's how the sulfate is converted into hydrogen sulfide. A carbon denitrator does essentially what you are suggesting, but sets water flow through the device to allow consumption of nitrate but not so slow that hydrogen sulfide arises.

I am not a fan of Marinepure due to the potential release of aluminum. Another concern is driving nitrate too low with them (that is the topic of a current thread in the chemistry forum from someone who is considering removing it). But many folks seem to use them OK.

These have more:

Hydrogen Sulfide and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-12/rhf/index.php

Water Changes in Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-10/rhf/index.php

Nitrate in the Reef Aquarium - REEFEDITION
https://www.reef2reef.com/blog/nitrate-in-the-reef-aquarium

 

[Cornerboy]

Thanks Randy!!

I found and read your hydrogen sulfide article last night. I had no idea that half-life's were that long. I thought hydrogen sulfide was much more volatile than that. Still I'm wondering how the skimmer, ozone, carbon, and the refugium would handle the inital wave if i wanted to try this...

Thank you sooo much for stearing me away from it. It's very appreaciated!! What, if anything, would be a better use of that space? Heaters i guess?

I had no idea about aluminum and I look forward to reading it your additional links!! :-(

 

[Cornerboy]

 

[Jose Mayo]

Once, I tried a multi-filament polypropylene rope inside a 30-meter hose (1/2 "hose and 3/16" multifilament rope), where the water circulated with a small pump (400 liters / hour). I named the experiment "high flow denitrificator". The hose, with the rope inside it, has to be rolled from bottom to top, one layer at a time, so it will not accumulate gases. The pump is coupled in the lower loop and the flow is made upwards, dragging the formed gases, starting in the sump and returning to the sump. I noticed that, in these dimensions, the water entered with pH 8.4 in the hose and left with pH 8.0 at the other end. It worked very well to eliminate nitrates and did not form H2S.

Denitrificador de alta vazão (by Jose Mayo)

Best regards

 

[Cornerboy]

Once, I tried a multi-filament polypropylene rope inside a 30-meter hose (1/2 "hose and 3/16" multifilament rope), where the water circulated with a small pump (400 liters / hour). I named the experiment "high flow denitrificator". The hose, with the rope inside it, has to be rolled from bottom to top, one layer at a time, so it will not accumulate gases. The pump is coupled in the lower loop and the flow is made upwards, dragging the formed gases, starting in the sump and returning to the sump. I noticed that, in these dimensions, the water entered with pH 8.4 in the hose and left with pH 8.0 at the other end. It worked very well to eliminate nitrates and did not form H2S.

Denitrificador de alta vazão (by Jose Mayo)

Best regards

Thanks Jose!! That is pretty high tech diy!! And easy to adjust.

That was kinda my thinking with the rubble and media bags and layers of acrylic. That it would be much easier to break down and remove or tinker with than a deep sand bed or mud, but might produce the same benefits.

 

[Jose Mayo]

What I believe is the "advantage" of this method is that, after a short period of "cycling", a bacterial film forms on the rope, which isolates its interior from the other environment inside the hose, although the water is flowing high around the rope and inside the hose, inside the rope is "stopped". This is what guarantees the low oxygen tension inside the rope and, by diffusing nitrate from the water back into the interior, creates microaerophilic conditions that promote denitrification, reducing the risk of using sulfate as a source of oxygen by bacteria in the inside the rope.

When using deep beds or "thick" media that hinder the diffusion of nitrate, the bacteria give sulfate as a source of oxygen and produce H2S.

Just a thought.

Best Regards

 

[Cornerboy]

So Jose, it looks like you are in a different Camp from Randy in the you have found the low oxygen compont to be a successful, useful part of maintaining a reef tank. What do you see as being the pros and cons? Any thoughts about the layer cake Rubble model I'm proposing above? I was thinking about pushing a gallon or two of water through it twice a day to simulate title changes... feed 2 gallons an hour, let it sit for 11, repeat. Of course I'm a novice and I have no idea what I'm doing

 

[Cornerboy]

Randy, I know your discouraging going down this road and I thank you very much for doing so! I'm not even 30% committed to the idea but I'm still playing with the idea. In theory I could control calcium and alkalinity with kalkwasser, nitrates with the hypoxic zone, and then I would primarily be looking at dosing magnesium (maybe strontium) IF I get all these pieces -parts in balance. Is that correct sir? (No SPS planned)

 

[Jose Mayo]

So Jose, it looks like you are in a different Camp from Randy in the you have found the low oxygen compont to be a successful, useful part of maintaining a reef tank. What do you see as being the pros and cons? Any thoughts about the layer cake Rubble model I'm proposing above? I was thinking about pushing a gallon or two of water through it twice a day to simulate title changes... feed 2 gallons an hour, let it sit for 11, repeat. Of course I'm a novice and I have no idea what I'm doing

No, I am not opposed to that already explained by Dr. Randy, what I am proposing are more permeable media to nitrate, so that the microaerophilic bacteria do not use the sulfate as source of oxygen, pre-condition for the formation of H2S.

In an "active" system, where you can control the flow of nitrate-rich water to offer bacteria, the risk of H2S formation is lower. In a "passive" system, deep sand beds, thick media and the like, the result depends on chance and the risk is greater.

Best regards

 

[SDReefer]

What is steering you away from carbon dosing? Just curious.