Complete Denitrification, a dream?

[Bifferwine]

Biff- Try not feeding as much, doing water changes isn't usually a very effective way at getting rid of nitrates because they come back so easily. Try locating the source. If you are going to have to feed so much as to have nitrates, which sometimes happen in heavily stocked tanks, there are commercial denitrators that would be good for the job.

I know, I don't overfeed. I feed about 4 cubes of frozen food a day for almost 30 fish.

The nitrates are so high because I haven't done water changes on this tank in a while. Nitrates were under control and close to 0 for a couple months when I was doing weekly water changes, but then I slacked off.

 

[McCrary]

Yea I don't think that 4 cubes is too much food for a tank your size. How much have the nitrates gone down since you started doing water changes?

 

[fatman]

Denitrification is the reduction of nitrates to nitrous gas. It is caused by a bacteria that lives where there is an absence of oxygen. In a reef tank that means either inside the live rocks porous structure or in the botton inch or so of a deep sand bed (5 to 6 inch deep bed). Jaubert has run tanks for years without water changes or skimmers and has low nitrates. He also has low bioloads and his tanks are years old. Live rock has very little denitrifying bacteria and therefore works slow, DSB have more denitrifying bacteria and perform this duty better but are still fairly slow due to a slow feed rate of nitrates to the bacteria due to the bacterial being in an area of little water movement. Actually most the food is brought to the bacteria by critters living within the sand bed. Do to these limits and the "need" for reefers to house to many corals and fish and feed to heavily we are pretty dependent upon water changes to remove any appreciable amounts of nitrates. That or as others mention control or remove the nutrients before they are converted into nitrates.

 

[Bifferwine]

Yea I don't think that 4 cubes is too much food for a tank your size. How much have the nitrates gone down since you started doing water changes?

I tested last night, and they're around 25 now!! Woohoo!! I don't have a very high bioload for my tank (the only "big" fish I have are a yellow tang, a kole tang and a trigger fish -- the majority of my fish are an inch or so long). I think my nitrate problem probably started with adding the trigger. I fed him A LOT in the beginning to keep him from eating my shrimp and other cleaner crew animals, and since he never touched them, I cut back quite a bit.

From now on, regular weekly water changes. But I'm not in the clear yet, I'm still going to do daily changes until my trates get below 5. Which will probably take forever now!

 

[daugherty]

good job at getting it down. i bet that took a lot of work.

 

[Bifferwine]

Thanks! Yeah, 30 gallons (10% in my tank) is a whole rubbermaid trash can. One of the big ones. I've been doing one of those at least every other day for 3 weeks now. Big kudos to NoobDeBiff for keeping me on track and helping out with every single water change!! And for carrying all the buckets of salt...

 

[fatman]

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