# Can't get nitrates down. Seachem matrix vs denitrate



## sayurasem (Jun 17, 2011)

I've been using eheim substrate pro for my biological media. Nitrates always reads 20ppm sometimes 40ppm. My problem is I can't never get my nitrates down to 10ppm or even desirably 5ppm.

So I would like to try something new something like Seachem Matrix or Seachem DeNitrate. After researching the two product is basically the same stuff just different pebble size.

After further research... Seachem DeNitrate only work best under 50gph of flow. I'm using Eheim 2213 and it has 116gph. Basically if I'm using DeNitrate it will defeat the purpose.

Hope you guys can chime in and share your info 
I really wanted to keep BKK, Taiwan bees, ect. but really nervous with my 20-40ppm of nitrates.


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## freph (Apr 4, 2011)

Add plants. Seachem Prime also neutralizes some nitrates iirc. Matrix will do nothing for your nitrates. It merely serves as a surface for your beneficial bacteria to grow (which process ammonia into nitrite and nitrite into nitrate).


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## GeToChKn (Apr 15, 2011)

It's not as much about the flow as it is getting the media in contact with very low oxygen water. This is why they chain 2-4 filters together. By the time the water has hit the 4th filter, it is oxygen depleted by going through the filter and not being able to exchange oxygen with the surface, like in the tank. In a low oxygen, or Anaerobic environment, bacteria that eat nitrates can live. In high oxygen, Aerobic ones lives, which eat the ammonia and nitrites. This is why some reefers do fluid sand beds. Deep under 8" of sand, there is little oxygen and their nitrates get eaten up. you get 1 or 2 of those prefilter boxes that people use and fill it with those medias above and it may help a lot. The denitrate has very small holes in it, so it tries to help the nitrate bacteria growing by being in a slower flow (<50gph) water and with small, deep pores, the idea is less oxygen makes it to the very center of the denitrate.


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## GeToChKn (Apr 15, 2011)

freph said:


> Add plants. Seachem Prime also neutralizes some nitrates iirc. *Matrix will do nothing for your nitrates. It merely serves as a surface for your beneficial bacteria to grow (which process ammonia into nitrite and nitrite into nitrate)*.


Not really true, read what I posted above. In a low-to none oxygen environment, Nitrate eating bacteria grow. Matrix is designed to get the bacteria to the middle of the media where O2 is the lowest. Other media will work if chain 3-4 canisters together or do some kind of DIY filter at the end of any canister to keep the water in the filtration chain the longest before it gets back to the surface of the tank.


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## sayurasem (Jun 17, 2011)

GeToChKn said:


> It's not as much about the flow as it is getting the media in contact with very low oxygen water. This is why they chain 2-4 filters together. By the time the water has hit the 4th filter, it is oxygen depleted by going through the filter and not being able to exchange oxygen with the surface, like in the tank. In a low oxygen, or Anaerobic environment, bacteria that eat nitrates can live. In high oxygen, Aerobic ones lives, which eat the ammonia and nitrites. This is why some reefers do fluid sand beds. Deep under 8" of sand, there is little oxygen and their nitrates get eaten up. you get 1 or 2 of those prefilter boxes that people use and fill it with those medias above and it may help a lot. The denitrate has very small holes in it, so it tries to help the nitrate bacteria growing by being in a slower flow (<50gph) water and with small, deep pores, the idea is less oxygen makes it to the very center of the denitrate.


Thanks for the reply!
I think this is why I have somewhat high nitrate. My substrate is akadama with 3cm (barely over the black rim) of depth. I guess I have no anaerobic bacteria whatsoever in my system.

So GeToChKn, what would you do with 1 eheim 22213? Stick with Matrix or DeNitrate? 
What would you do if you have 4 filters chained together? would you load it Matrix or DeNitrate?


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## freph (Apr 4, 2011)

You'd think the oxygen content would be the highest where the most flow is (filter itself), no? To me this means that the filter should just be chemical/biological (aerobic bacteria)/mechanical and the substrate (where least oxygen is likely to exist) is where you'll find the most anaerobic bacteria. I may be wrong, though.


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## sayurasem (Jun 17, 2011)

freph said:


> You'd think the oxygen content would be the highest where the most flow is (filter itself), no? To me this means that the filter should just be chemical/biological (aerobic bacteria)/mechanical and the substrate (where least oxygen is likely to exist) is where you'll find the most anaerobic bacteria. I may be wrong, though.


This is what I realize too. But seachem claimed DeNitrate can hold anaerobic bacteria if its placed in a canister filter with less than 50gph of flow. Then again what canister filter has less than 50gph flow :confused1:?


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## GeToChKn (Apr 15, 2011)

sayurasem said:


> Thanks for the reply!
> I think this is why I have somewhat high nitrate. My substrate is akadama with 3cm (barely over the black rim) of depth. I guess I have no anaerobic bacteria whatsoever in my system.
> 
> So GeToChKn, what would you do with 1 eheim 22213? Stick with Matrix or DeNitrate?
> What would you do if you have 4 filters chained together? would you load it Matrix or DeNitrate?


You won't get aerobic bacteria in any normal substrate, regardless of depth really because there is no flow. With too deep of substrate, especially sand you run the risk of sulfide pockets because the gas builds up.

A member on a local forum and bought one of those pre-filter canisters and filled it with denitrate and got his nitrates down just running it after the canister output. 



freph said:


> You'd think the oxygen content would be the highest where the most flow is (filter itself), no? To me this means that the filter should just be chemical/biological (aerobic bacteria)/mechanical and the substrate (where least oxygen is likely to exist) is where you'll find the most anaerobic bacteria. I may be wrong, though.


Flow, and intake of a canister has nothing really to do with O2 content of the water, just like an airstone doesn't add any O2 to the water at all, airstones make bubbles which break the surface tension of the water which cause it to exchange gases with the air, thus adding O2 to the water, to roughly equalize itself with the O2 level of the air, and CO2 level as well. Even if you don't run CO2 in your tank, running an airstone actually adds CO2 to the water.

I'm sure of the exact process of why water that stays in a canister or series of canisters, etc gets more depleted of O2, maybe because it's being robbed of it's O2 to help saturate the water around it with more O2 or something, that part I don't know, but it does, and when it does, anaerobic bacteria will grow and go mange, mange, mange on nitrates. Looks up fluid sand filters. They're pretty neat and actually not that hard of a thing to do for a DIY.


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## sayurasem (Jun 17, 2011)

GeToChKn said:


> You won't get aerobic bacteria in any normal substrate, regardless of depth really because there is no flow. With too deep of substrate, especially sand you run the risk of sulfide pockets because the gas builds up.
> 
> A member on a local forum and bought one of those pre-filter canisters and filled it with denitrate and got his nitrates down just running it after the canister output.


May I ask if that member from a local forum has any problem with the canister motor? If I can recall correctly its a no-no to have blockage after the canister itself, thus putting pressure on the motor/ shaft.


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## GeToChKn (Apr 15, 2011)

sayurasem said:


> May I ask if that member from a local forum has any problem with the canister motor? If I can recall correctly its a no-no to have blockage after the canister itself, thus putting pressure on the motor/ shaft.


It's not a blockage though, it's just running through more media. If it was dangerous, would people run 4 canisters chained together.

As far as restricting the outflow somewhat on a canister filter by either ball-value, reducing pipe size, running through another canister/container of something, etc, read through this.

http://www.plantedtank.net/forums/showthread.php?t=189034


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## sayurasem (Jun 17, 2011)

GeToChKn said:


> It's not a blockage though, it's just running through more media. If it was dangerous, would people run 4 canisters chained together.
> 
> As far as restricting the outflow somewhat on a canister filter by either ball-value, reducing pipe size, running through another canister/container of something, etc, read through this.
> 
> http://www.plantedtank.net/forums/showthread.php?t=189034


Thanks for clear it up for me!
btw, back to my original question... would you use Matrix or DeNitrate?


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## Bluek24a4 (Mar 16, 2010)

Are there Nitrates in the water that you use for water changes?


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## sayurasem (Jun 17, 2011)

Bluek24a4 said:


> Are there Nitrates in the water that you use for water changes?


Nope. 0ppm 100% RO


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## Bluek24a4 (Mar 16, 2010)

Maybe your canister filter is being a Nitrate farm like the salt water guys say. When was the last time you cleaned it?


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## xenxes (Dec 22, 2011)

Bacteria eat nitrates? What? I wasn't aware that any media could remove nitrates, trap it perhaps. I imagine the media will become saturated eventually and end up pouring it back into the water column.

Add plants sir, or do more water changes. Nitrates cannot accumulate without ammonia -> nitrites. Throw in some floaters or fast growing stems to convert it to plant mass.


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## sayurasem (Jun 17, 2011)

xenxes said:


> Bacteria eat nitrates? What? I wasn't aware that any media could remove nitrates, trap it perhaps. I imagine the media will become saturated eventually and end up pouring it back into the water column.
> 
> Add plants sir, or do more water changes. Nitrates cannot accumulate without ammonia -> nitrites. Throw in some floaters or fast growing stems to convert it to plant mass.


I'm still kinda confused too...
*Ammonia* -> aerobic bacteria -> *Nitrite* -> aerobic bacteria -> *Nitrate* -> anaerobic bacteria -> *???*

I do weekly water change 10% (2 gallon) on my 20g long tank. I feed my shrimps every 2 days.

My plan is to sell all my CRS and replace them with BKK. My CRS thrives in this 20ppm nitrates, but I don't know about BKK. 

Now I found two things that made my nitrates quite high. One is shallow substrate, the second is lack of plants.

Btw does IAL, cholla woods, and alder cones produce nitrate as they decompose? Because I'm sure I got tons of them in my tank.


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## xenxes (Dec 22, 2011)

Ammonia -> (Nitrosonomas) -> Nitrite -> (mainly Nitrospira, also Crenarchaetoa, Nitrobachter, +others) -> Nitrates -> (What bacteria strain eats Nitrates? You need special Seachem media to grow these!?)

Any decaying matter produces Ammonia at various rates, decaying organisms faster than decay plant matter. This gets converted down to Nitrites then Nitrates.


I found this... http://israel21c.org/environment/bio-filter-blasts-nitrates-out-of-the-water/



> Nussinovitch, an expert in biological carriers, and van Rijn, a specialist in bacteria, paired up to develop a bio-filter composed of tiny Styrofoam-like white beads that carry nitrate-eating bacteria. When added to a water well, aquifer or aquarium, the bio-filter does its job effectively and cheaply.


Does not say the bacteria strain. Weird. 

Well, I know for sure plants work, so try that  Or you'll have to up those water changes, which is also bad since parameters will vary. So.. perhaps 10% twice a week. Plants = easier.


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## GeToChKn (Apr 15, 2011)

sayurasem said:


> I'm still kinda confused too...
> *Ammonia* -> aerobic bacteria -> *Nitrite* -> aerobic bacteria -> *Nitrate* -> anaerobic bacteria -> *???*
> 
> I do weekly water change 10% (2 gallon) on my 20g long tank. I feed my shrimps every 2 days.
> ...


I never said shallow substrate causes it. Plants do help eat the ammonia in the first place before it can even hit the filter.


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## Bluek24a4 (Mar 16, 2010)

sayurasem said:


> I'm still kinda confused too...
> *Ammonia* -> aerobic bacteria -> *Nitrite* -> aerobic bacteria -> *Nitrate* -> anaerobic bacteria -> *???*


Nitrogen Gas.


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## GeToChKn (Apr 15, 2011)

Bluek24a4 said:


> Nitrogen Gas.


Which will off-gas with surface agitation if it's greater than the atmosphere.


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## sayurasem (Jun 17, 2011)

I know its not planted tank but...

Before Matrix: http://youtu.be/qbMjf9UyeLE
After Matrix: http://youtu.be/wlXPNJ4cCzI


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## GeToChKn (Apr 15, 2011)

sayurasem said:


> I know its not planted tank but...
> 
> Before Matrix: http://youtu.be/qbMjf9UyeLE
> After Matrix: http://youtu.be/wlXPNJ4cCzI


That really doesn't prove anything, he had it in a skimmers, skimming off the surface, meaning O2 exchange with the surface, meaning higher O2 levels, meaning the Anaerobic bacteria never get a chance to form. Getting Anaerobic bacteria present is not dependent on the media for the most part, it's getting O2 starved water over the media. With a slow, sealed 40gph filter, you can use lava rock, pot scrubbers, whatever and get Anaerobic bacteria to grow.

The Denitrate tries to help this along by making very small pores in the media and saying you need it in a slow flowing filter. Again, with a proper filter setup, you can use anything. Look at the fluidized sand filters. They use pool filter sand, play sand, whatever kind of sand they have. The idea is that the sand, which does have a big surface area, but by the top of the long chambers they use for sand filters, the sand is starved of O2 and the Anaerobic bacteria grow, thus removing nitrates.

The true answer to your problem is find the source that is causing the nitrates in the first place and not try and band-aid the solution. Sometimes you can't find it and it's something in substrate, etc and it's better to just nuke a tank and start over. lol.


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