Jump to content
Top Shelf Aquatics

Any hints for biological reduction of Nitrate?


krourke85

Recommended Posts

Hi,

 

My goal is to keep my tank Nitrates low organically. My 8 Gallon from IM has 3" of Caribsea Live Sand and live rock piled to the surface. Still, my Nitrates are rising.

 

Any suggestions?

 

I know the live sand came with denitrifying bacteria, but is there any bacteria supplement that would still help?

 

I'm looking for solution besides skimmers and water changes. How do I convert Nitrate into N2 gas biologically!

 

Thanks :D

Link to comment

A 3" sand bed isn't deep enough and there probably won't be enough surface area to accomplish your goal. You could do what you are looking to do with a remote deep sand bed (RDSB). You should still perform water changes and remove wastes, but (after it becomes established) you shouldn't have to perform water changes for the sole purpose of nutrient export.

 

A RDSB is typically a covered 5 gallon bucket, filled with fine sand. The sand should be 6 to 8" deep to support denitrifying bacteria. Mechanically filtered water is pumped up into the bucket and an overflow drains it back into the sump or display tank.

 

It seems a little bit of overkill to implement a 5 gallon filter for an 8 gallon tank. Especially considering that you will still need to perform water changes. The beauty of a nano tank is that large water changes are easier and cheaper than on a large system; and they can/should be used to remedy a wide variety of issues that might affect your tank (nitrate included).

 

As farkwar stated, carbon dosing with a powerful skimmer is another nutrient export mechanism. This creates an ultra low nutrient system. It's a different type of system than we traditionally keep, and it has its own unique challenges due to the lack of nutrients in the system.

 

As Dr.Brain Coral said, a macro algae refugium (or algae scrubber) would make the most sense. These lower nutrient levels in the water as the algae uptakes the nutrients (phosphate and nitrate). It is exported as the excess algae is physically removed from the system.

Link to comment

There are tanks where they don't do many water changes. It comes up from time to time. Not very popular around here. It sounds like you are very experienced, so water changes are your best bet for controlling nutrients. Good luck

Link to comment

There are several nitrate filters on the market, this is the one I've heard most about: http://www.aquaripure.com

 

But Googling "denitrator" yields many results and DIY options. I've never used one, they seem like more work and expense than just practicing good husbandry and changing the water regularly.

 

My FW planted tanks both run at zero nitrates now that the plants are well established, I still do 25-50% water changes 1-2 times a month. I'm also having good results in my reef tank with once a week detritus removal combined with running chemi-pure blue and elite a few hours a week (both accomplished using a turkey baster thing and a Magnum HOT 250) followed by a 15-20% water change.

 

It's not just nitrate that is an issue.

Link to comment

Thanks everyone for your input.


I do use my sediment vacuum but part of the challenge in a nano tank is seeing how strong I can make the biological filters. Why remove only 20% of your nitrates every other week when you can have 100% of them metabolized instantly!

 

As Dr.Brain Coral said, a macro algae refugium (or algae scrubber) would make the most sense. These lower nutrient levels in the water as the algae uptakes the nutrients (phosphate and nitrate). It is exported as the excess algae is physically removed from the system.

 

Doc/Seabass: Is that an Aquaclear 20 moded into a algae scrubber you suggested? I've let Caulerpa cover my tank and am currently exporting about a tennis ball worth every month :D

Eventually I want to move it into the back inside the media basket chamber. I'm thinking of using the Magnafuge LED and some scaffolding made from PVC egg crate and super glue to make a refugium. What do you think??

 

Chadf: I believe you are right, but the CaribSea instructions said 2lbs/gallon was enough also. I have emailed them to see what they have to say.

Link to comment

Deep sand bed and a tank full of macroalgae is what I would try.

 

but.... waterchanges are not just for nitrate removal... they replace trace elements you can't/don't test for but it really depends what you plan on keeping and if you want it to grow quickly.

 

I am guessing this is some sort of experiment?

 

Also for a deep sand bed, try 6 inches of sugar sized fine sand. The coarse stuff won't work.

 

Something like this (photo of seabass's tank, hope you don't mind, I just love this photo):

 

021311a.jpg

Link to comment

Wow, great photo. I had to do a double take, at first I thought is was a shallow tank and the sand bed was the stand. I often wonder how long glass like that stays pristine until algae starts growing.

 

I guess you could call this an experimental tank. I recently started getting the impression that a lot of LFS push a lot of stuff on hobbyists that isn't necessary. Their stuff works, but there are better solutions and they are often cheaper or free. I think using macroalgae instead of phosphate removers is a great example.

 

I love the idea of setting up a bigger tank where I pick up live rock, and sand while scuba diving, use ocean water for water changes and have a massive skylight above the tank.

 

Before people get upset, all live rock in Australia is local. Importing it is illegal. And I would still use farms for fish and anemones.

Link to comment

I love how there are many ways to accomplish the same thing in this hobby. They each have their ups and downs. Macro is beautiful but some people don't want it in their display tank but the fuge also would need to be fairly large to be as effective as a reactor which takes up space vs just a small reactor. Ofc the positives of macro are low cost and cultivating pods. I have 1 tank utilizing macro and 1 tank utilizing GFO because 1 tank I am cultivating pods for mandarins and the other has space constraints.

Link to comment

another way would be a big skimmer and carbon dosing (vodka, vinegar, no3po4-x, or solid carbon such as biopellets), this would be a biological reduction as well as the carbon fuels bacteria and the bacteria consume nitrate and phosphate.. the only problem is that it's not really practical on a nano imo, plus you said no skimmers or water changes..

 

a turf scrubber would be another biological method, as the algae grows it consumes n&p, in the same way macro algae would but in a much more aggressive manner.. this would (IMO) be an easy thing to add on, for such a small tank you could simply add the HOG (hang on glass) unit and likely see significant results..

 

as far as simply denitrifying, that's the million dollar question.. some say cryptic zones some say dsb's, some simply say it happens with time (and you really can't rush things in this hobby).. I don't think any bacterial additive is just going to make it happen over night..

 

there's also a thing called a "fluidized sand bed" that basically is a reactor with sand or some other media with lots of surface area that gets colonized by bacteria and processes waste.. that would be an easy add (as easy as buying a reactor and some sand).. they were big for a while, particularly with overstocked large fw systems.. not really sure why they didn't become more popular with the reef crowd.. I think they stop at no3 though, and if you're trying to denitrify, that wouldn't be the answer..

Link to comment

Personally I swear by a refugium with cheato and LOTS of lighting.

No dinky so called "refugium lamps" that some stores want to push on you, but par 38 flood lights.

Link to comment

There is Seachem Stability that contains denitrfying bacteria. I use it weekly in my seahorse tank after a WC. One capful per 20 gallons.

Link to comment

Thanks everyone for your suggestions.

 

My new plan is to try removing all the live rock every month and doing a thorough vacuum/water change. I'm also going to set up a refugium in the media basket chamber (IM even suggests it as an option on their website). My LFS showed me a 6W LED 6400k from aqua one. I know it's a cheap brand, and I wasn't expecting much, but it's actually a perfect light for this.

 

I think my big thing is that I want everything living in the water column to survive getting through the filter. This means no skimmers, fluidized bed filters, and I even want to keep filter floss to a minimum (ideally 1 day a week). The benefits of this are huge because you get a truly complete food chain and organisms are able to reproduce without having their spawn caught in filter floss and dying. Ideally I would like to find a water pump that wouldn't kill fry, but I don't think that exists, at least not one that will turn over a tank 20+x/hr.

 

 

Below is an email I got back from CaribSea regarding the effectiveness of 3" of their live sand with denitifying:

 

Your email query was passed along to me about deep sand beds. 3" will do some good de-nitrification. You are correct in that there are many schools of thought on this matter recommending deeper beds. Current thinking is 3-4" is plenty to get benefit but the 7" works too. The thing with such a deep bed is that it starts to negatively impact the aesthetics of the aquarium. I use 3" or a little more as that gives me de-nitrification and does not fill the tank 1/4 of the way up with sand.

Link to comment

I don't think I'd remove the live rock, every time you pull it out you risk die off and a new cycle. Just blow it off well on a regular basis and try to get the detritus out of the system (siphon, sponge....)

 

I am also going for a full 'ecosystem' in my tank, that's the biggest draw of saltwater over fresh to me. I started with a HOB refugium but noticed way more critters in the tank than in the fuge, possibly because they had to be sucked through the pump to get in there. I've since removed it and am running 3 Hydor Koralia nano 240 gph pumps. I think these are pretty gentle, I routinely see food go through them and come out the same size. I'm really looking forward to the RipTide gyre (or whatever they're calling it now), it looks like it will give a lot of flow with minimal damage to 'wildlife'. I love all the pods in my tank and the filter feeders definitely appreciate that they're food isn't constantly filtered or skimmed out and they are just as interesting as the fish.

 

I don't think there's much chance of fry surviving without a very specialized set up but certainly pods, sand inhabitants, etc have a better chance of surviving longterm if they aren't reproducing on a sponge filter that's changed regularly or otherwise being sucked out of the tank.

 

I would really love to do a live rock only tank and just see what sprang up. I think without fish and some of the more predatory CUC the pods and other small life would flourish. And I'm sure there would be plenty of macro algae and sponges, etc that would help to keep up water quality. My current tank is only about 3 months old though so I want to get some more experience with all this before I add yet another tank to maintain ;)

 

Good luck with yours

Link to comment
  • 4 weeks later...
  • 3 months later...

Hey Everyone,

 

My nitrates have just dropped to 0.0!

 

I thought it would be worth updating this post to let everyone know how it happened.

 

I had been struggling with nitrates as my Nuvo 8 nano has no skimmer and a relatively heavy livestock load. I have tried a lot of things to lower the nitrates biologically with little success. For months the nitrates were hovering between 10-40ppm and I was forced to limit my anemone feeding.

 

A month ago I installed a DIY 70 watt metal halide lamp. My nitrates are now zero!

 

Has anyone else had a similar experience?

 

I was thinking maybe my anemones were dumping nitrates into the system as they were being forced to use protein for fuel instead of sugar grown from the lighting (which was terribly inadequate)

Link to comment

So the light allowed you to drastically reduce target feedings. Still, you must have some biological nitrate reduction (probably from the 3" sand bed) for the nitrate to drop so much. Some nitrate isn't necessarily bad (without any phosphate and nitrate, coral growth/health may suffer). Also, remember to keep your sand bed as clean as you can (with good flow, and siphoning detritus off of the top of the bed).

Link to comment

. How do I convert Nitrate into N2 gas biologically!

 

 

Thiobacteria reduce NO3 to N2.

 

You can use sulfur as your feed media, like biopellets kinda. In a nitrate reactor.

 

They can use iron pyrite as well, though i've not seen one nitrate reactor use this.

 

 

I had been wondering how to seed the reactor with bacteria. Not wanting to just luck upon them coming in on live rock. MetroKats build thread has a source of bottled thiobacteria, which some posters described as smelling like a mixture of ass mixed with rotten eggs.

Link to comment

Run a plenum of some degree if you can run a sump. I'm my experience the best method you can use. I ran a huge plenum area in my sump and I ran zero nitrates in my 75 gallon the whole time it was up. Between the plenum and the fuge full of chaeto, it was money!

Link to comment

Archived

This topic is now archived and is closed to further replies.

  • Recommended Discussions

×
×
  • Create New...