Aerobic Denitrification With Vodka Dosing??

[jarrod0987]

Been reading many articles on Vodka dosing lately. Sounds succesfull. I am to understand that the chemistry is as follows:

If O2 is present, The O2 and carbon source (Vodka) are consumed.

However, If no O2 is present then Nitrate (NO3) and Carbon source are consumed. Nitrogen gas is produced.

This seems to imply that an anerobic sand bed or other anerobic condition would be required for vodka dosing to produce the desired result.

However, I have read posts that state people who have DSB may have to wait longer for the backlog of waste trapped in the sand to be consumed.

To me this implies in some cases there was no DSB...or any sand bed at all??

I have also read statements to the effect of "My next sump won't have a DSB".

So my question is...Can I have vodka dosing to remove nitrates without any kind of sand bed or anerobic enviroment at all?

 

[melosu58]

I have never tried it but I did find this in my links. Dont know if it helps or not.

Vodka Dosing by 'Genetics' and 'Stony_Corals' - Reefkeeping.com

 

[iDream]

i have heard multiple times that it does eventually cause cyanobacteria outbreaks

 

[mr_X]

i've used vodka with success. i use it on a tank i maintain at a local gym. the water is crystal clear and a recent dinoflagellates outbreak was all but wiped out by it in just about a week. the corals look healthier, and the purple valida that has been there since the beginning has gained a lot of color.
the sand bed is 2" for aesthetics.

 

[jarrod0987]

Yes, But do any of you have Sand beds in these systems or are there no sand beds? I'm trying to find out if I can eliminate a sand bed all together.

 

[mr_X]

a 2" sand bed is going to give you zero denitrification. it's the same as no sand bed, from a nutrient reduction standpoint.

 

[Gregcoyote]

If I were to use sand for anything, I would use a "fluidized" system. I have never had any luck with just plain sand. I do use a crushed shell bottom in my reef tank for buffeting alkalinity, but not to reduce any organics.

 

[Trout11B]

Can you explain what a fluidized system would be in regards to the sand bed?

 

[Gregcoyote]

Yes, in a fluidized sand filter, a very fine grain sand is used and a pump pushes water from the bottom of the column to the top, keeping the sand particles suspended. This provides an immense amount of surface area for bacteria to form, making these filter very efficient. They are available on line and are quit inexpensive.

 

[mr_X]

the crushed shells at the bottom of the tank trap detritus. i guess you are vacuuming the bed on a regular basis. i like to use the aragonite sand to do the same thing without the maintenance. fluidized bed filters were popular a few years ago, but i'm not sure they were considered "very efficient".
they don't convert nitrate. they tend to build up nitrates from what i remember. i think they were more popular in a fresh water, planted tank application.

 

[Gregcoyote]

That is why I keep Watchman Gobies, they dig constantly. The forced flow sand filter is still being used by all the major aquariums in the country coupled to a protein skimmer. I think they are far more efficient than bio balls or the like. You are right about the nitrates, that is why I also run a large algae turf scrubber. The only non-chemical way I know to remove nitrate is by growing and discarding algae.

 

[mr_X]

but why run a fluidized bed filter and a turf scrubber? why not just run the turf scrubber? super heavy bio load?

 

[Gregcoyote]

I probably could, but I like the fact the protein skimmer directly lifts long chain organics directly out of the water. The sand filter is basically a backup to the algae scrubber, as it cycles itself (found that out the hard way, the algae actually changes it variety and characteristics). As long as you aren't adding chemicals, I don't think you can over filtrate the water. My system is almost always run "open" with no fine filter blocking small organism growth. The only time I filter particulate matter is if I am stirring things up and cloud the water.

 

[mr_X]

i agree with not being able to over filter. i'm also an advocate for a massive protein skimmer (relative to tank volume) on systems over...about 40 gallons or so.

 

[Gregcoyote]

Amen. A really vigorous protein skimmer is at the heart of a good filtration system for a reef.