Nitrate Reduction - more in depth...

[gummi]

Hi,
I know we're probably tired of this question as it's asked often but I still haven't really gotten an answer to this question:

What reduces nitrates?

I thought that fish release waste that turns to ammonia. Ammonia is consumed by bacteria in LR to produce Nitrite. Nitrate is consumed by LR to create nitrates. Nitrates are lowered by water changes.

So if LR doesnt cycle nitrates, how do so many people have 0 nitrates? Do copepods help with this nutrient export? I know mangrove plants will also reduce.

This might be a simple answer but I haven't seen to find it. I could be under the wrong impression that bacterial in LR will reduce nitrates because it seems that aquariasts that have an abundance of rock never have any nitrates.

Comments?

 

[gummi]

I also know tha there are de-nitraters that can be bought but I'm trying to stay with a KISS style system.

 

[drummereef]

The nitrifying bacteria in your live rock does break down nitrates. Areas to look into on your filtration are anything that can collect detritus. Filter sponges, pads, floss, and 'man made' bio media, are all problem areas. The use of macros, such as chaeto, can also help in reducing nitrates. I have a sumpless 40g system. I rely on my live rock and deep sand beed for nitrate reduction.

 

[danch]

You need areas of low oxygen content to get the bacteria to reduce nitrates - they're basically forced to grab the oxygen off of the nitrate (NO3) so that they can use it in their metabolism. This leaves Nitrogen to escape as gas.

Typical low oxygen places are the insides of porous rocks (live rock) or the lower layers of a deep sand bed.

 

[WinnipegDragon]

Deep sand bed or nutrient export from your Refugium seem to be the two best options that I can see.

 

[gummi]

My nitrates aren't super high (10 PPM) but it may be due to the fact that I have a SSB and a small refigium. I am lookign for a Cheato colony to start growing it in my fuge so that could be where teh 10 PPM come from in my system.

I don't have any sponges, floss (etc) in my tank so most likely it's detrius on my sand bed or something. I have 80lbs of LR (Haitian Lettuce, Bali) and 5lbs of LS in my 'fuge. System is 65g with a 20 g sump. Yeah, I know I could use some more LR.

 

[kevin2000]

A nitrate of 10 is pretty low and unless your keeping nitrate sensitive corals many would say thats fine. You may find you can take that down to zero by cutting back food a bit, a minor increase in frequency/amt of water change, or perhaps a bit more live rock.

 

[papagimp]

Here ya go...in depth.

Nitrates as mentioned are formed when aerobic bacteria consumes the ammonia, converts this into nitrites and then further into nitrates. Aerobic bacteria will not cosume the nitrates though. For this you will need anerobic zones, or area of low/no oxygen where anerobic bacteria will colonize. The is the same bacteria that forms deep within very porous rock surfaces or deep in a sandbed. As the aerobic bacteria releases nitrates the anerobic bacteria will utilize it and reduce your levels.

I do agree with Kevin on this, 10ppm isn't that bad. Most sources I look to claim that keeping nitrates under 30ppm is okay.

You will want to watch the smaller sandbed for detrutus buildup as well as areas around the tank, in the rockword, and behind the rockwork with area's of no flow or dead spots. These areas will trap detritus easily and the buildup will only cause a rise in nitrates. As well as having other methods of biological filtration...such as not cleaning a sponge prefilter on your return pump and the sponge builds up aerobic bacteria...this will help filter the tank, but since the nitrates are being released so far from the aneriobic zones, they won't have the chance to reduce them. This is one of the single most imporatnt reasons IMO to keep all mechanical filtration methods clean as can be and often. And if you utilize other forms of biological filtration, such as bioballs or sponge filters, or even a HOB, the biological media should be removed...keeping only the mechanical filtration pads/media in place. And these will need to be cleaned often to prevent aerobic bacteria from colonizing too much on them.

80lbs of rock should be okay, but more would allow a better chance for more anerobic zones, especially since the sandbed is smaller.

 

[gummi]

I had sponges in my sump but they did exactly that... caught too much 'crap' and build-up so I removed them. I'm going to try to put them back in and wash them regularly.

80lbs of haitian rock, 10 lbs of bali, 5 lbs of live sand is what i have.

I have no corals at all. I just have a FOWLR setup with really hardy fish (2 percs, 1 yellow tang). The system plan is for fish-only and maye some hardy inverts/softies but not full reef.

 

[McCrary]

If your tank is for fish and not coral then you should be fine with some nitrates present. Fish don't seem to mind them unless concentrations get really high.