Removal Of Nitrate

[petertr]

I'd love to believe this is correct, but I'm too skepticle to do so.....

I have a Rio box filter, which comes with 2 fine sponges to remove particles, then 1 coarse blue filter for bio, and then there is a green coarse "nitrate removal filter".


I've struggled to find much information on this, other than it is something along the lines of a bateria that feeds on nitrate, and turns it into Nitrogen gas?



Since I put my discus in, I've been running regular water tests - and I've had zero ammonia, nitrites and nitrates the whole time.

Could the nitrate filter actually be working?


If so, is there a reason why I'm performing 2/3 15% water changes every week?

 

[raptorrex]

humm, I've often wondered about them too. but never used one, nor intend to. looking at the change out time, it looks little more than a ploy to get more money. and if they really work, would we all not be using them and shouting their worth all over?

 

[Mr Bliss]

Bacteria will only reduce Nitrate under anaerobic conditions, and as far as I know this works very poorly in freshwater, generally leading to a partially reversed nitrogen cycle rather than complete reduction to nitrogen gas, so I'm a bit sceptical about the nitrogen removal sponge working on a biological basis without some kind of a chemical catalyst. Most likely it might be made of a material that's able to chemically bind nitrates, in which case it'll probably become saturated at some point and stop working. But I might be wrong.

Nitrates aren't the (only) reason we do water changes, though. In planted tanks, we actually add nitrates because the plants consume nitrogen faster than the fish release it. Other reasons to do water changes:

• The bacteria of the nitrogen cycle use bicarbonate as their sole carbon source, meaning that they gradually lower the KH of the water, which can eventually lead to a pH crash if you don't restore the buffering capacity (water change being the simplest method). Some plants, like Vallisneria, readily use bicarbonate as a carbon source as well.
• Plants (and fish) take up trace elements from the water that need to be replenished.
• All kinds of inorganic compounds accumulate in the water, particularly if you replace a lot of evaporated water compared to actual water changes, and may be harmful in high concentrations. For example, some tap waters contain copper at a concentration that becomes lethal to aquatic life if you let it accumulate.

 

[waterdrop]

Yes, two great and related topics here and mr bliss has done a great job answering them, so I'll just add a couple of small comments:

1) re Why should I bother with water changes if my nitrates are testing out at zero levels?

As mr bliss said, nitrates are not (by any means) the only reason we do water changes (and he gives several examples.) In fact, nitrates are really used kind of like the "canary in the coal mine" saying, that is, its often just a convenient harbinger that we use as a reminder to do water changes, partly because its relatively easier to measure than all those other trace things. All sorts of trace organics and inorganics will build up in the water, especially if evaporated water is replaced, and they need to be periodically removed. I particularly like mr bliss answer because he also points out that there are trace minerals and things that also need to get -added- by the incoming tap water because they may have been used by the fish and plants - this is also important. If water changes are not performed on a regular basis (and we're talking normal, average aquarium hobby practice here, not special very experienced situations that are sometimes discussed) and trace materials are allowed to build up, you can have the situation arise called "old tank syndrome." In that situation, the fish have very gradually been acclimated to mineral and other trace contents that are very different than the source or tap water. At some point, when a water change finally happens, the fish may be subjected to such a sudden change in these parameters (often types of parameters that are hard to manage) and the fish will die.

2) Removal of nitrates by means other than water changes

Somewhere on TFF (I should go looking...) there was a really big discussion of the subject of nitrate filters. When I first read it I was shocked, not knowing that they even existed. I thought, "Wow, this should be great." But the bottom line, it turns out, is that nitrate filters are, at least in the opinion of the thread participants, way too much trouble and expense for what they do. They turn out to be a lot more trouble than a water change and that is especially true when one considers number one above, where we've just said that water changes will need to be done anyway! The nitrate filters were indeed anaerobic contraptions, involving long water runs to meet the extreme surface area requirements involved if I remember correctly.

~~waterdrop~~

 

[raptorrex]

Somewhere on TFF (I should go looking...) there was a really big discussion of the subject of nitrate filters. When I first read it I was shocked, not knowing that they even existed. I thought, "Wow, this should be great." But the bottom line, it turns out, is that nitrate filters are, at least in the opinion of the thread participants, way too much trouble and expense for what they do. They turn out to be a lot more trouble than a water change and that is especially true when one considers number one above, where we've just said that water changes will need to be done anyway! The nitrate filters were indeed anaerobic contraptions, involving long water runs to meet the extreme surface area requirements involved if I remember correctly.

~~waterdrop~~

you can get a nitrate reactor for a 180L tank for £50, though it is not true they need to be anaerobic as stated, you can use sulphur, which is turned to sulphuric acid which is converted by a alkaliser, often no more than crushed oyster shell, the result is fresh water. however if you compare them to RO units, which some use for nothing more than high tap water nitrate readings, they do begin to make more sense. they cost about the same, do not destroy the water, need no additives to make the water safe again, they don't waste vast amount of water and the biggest plus is virtually 0 nitrates in the tank at all time after set up.

as for water changes, well each to their own. some on here do several a week and claim their fish are happier for it, though i must admit i don't see why. others do them every week, even some do it every month. all claim their fish are happy and healthy. so can they all be right, my guess is probably!

 

[petertr]

Good replies. Thanks.


So can anyone suggest why I have no nitrate in my tank - not a bit - after 3 weeks of testing.

 

[rabbut]

Either a dodgy test kit or the sponge does work. My bet would be on the sponge acctually working though... Bacteria is IMO unlikely to remove the nitrate here, as the filter is airobic... I never heard of nitrate filter's working on sulphor before mind, so can't realy say if that is the case here, but where would the bacteria for the sponge come from? These sponges aren't shipped wet are they? I find it hard to belive that the bacteria can live on a dry sponge, and building a colony in the tank would take time like cycling...

I think they are a resin based contraption that adsorbs the natrate (and possibly other compounds?) from the water, in a similar way to carbon removing meds and organic smells/colourations. It becomes saturated eventually, but if you are lighly stocked and waterchanging large ammounts weekly as you should with Discus, the resin should last a long while, as little nitrate will be going into it

A dodgy kit can also lead to false lows, so the sponge working deffinately isn't the only option. Also, waterchanges may be keeping the natrate below the lower threshold of testing for your kit.

Many resins also remove ammonia and ammonium, so beware that some nitrate filter medias can mess up your biological filter. There isn't a right lot of information out about the Juwel media, so this will make many skeptical as-to the safeness of this media. It's like using cat litter to solve a nitrate issue (can be done ) It stops nitrate forming in the first place by removing the ammonia that breaks down into it, but out-compeeting the filter bacteria. This coupled with waterchanges will bring nitrate back down, but it isn't a safe thing to do...

HTH
Rabbut

 

[petertr]

By the way, the tank has been established for about 2 years. So cycling etc isn't an issue.

I guess its just water changes then.


Thanks

 

[Dave Spencer]

I have a Rio box filter, which comes with 2 fine sponges to remove particles, then 1 coarse blue filter for bio, and then there is a green coarse "nitrate removal filter".

I've struggled to find much information on this, other than it is something along the lines of a bateria that feeds on nitrate, and turns it into Nitrogen gas?

If you take a look inside the Juwel green nitrate sponge you will find a small capsule.

Dave.

 

[Gilli]

Just a thought - are you using a proper liquid test kit and performing the nitrates test correctly? The only reason im asking is i've done the test hundreds of times but the last time I did it I forgot to shake the second bottle before adding to the test tube and under those circumstances the result will always be 0.

 

[petertr]

Just a thought - are you using a proper liquid test kit and performing the nitrates test correctly? The only reason im asking is i've done the test hundreds of times but the last time I did it I forgot to shake the second bottle before adding to the test tube and under those circumstances the result will always be 0.

Yes, I have a liquid test kit - Its 3 or 4 stages. I add some power, then some chemicals - then shake for 1 minute - then add another chemical.

Haven't done a water change for 5 days now, as I was away at the weekend - so Ill give it a go tonight.

If you take a look inside the Juwel green nitrate sponge you will find a small capsule.
Dave.

Do you know anymore about it? Does it "reset" whenever I wash out the filter, or should it run out eventually? Sorry, totally clueless here!

 

[Dave Spencer]

Do you know anymore about it? Does it "reset" whenever I wash out the filter, or should it run out eventually? Sorry, totally clueless here!

I have no idea I`m afraid, as I add nitrates, so I have no use for them.

Dave.

 

[petertr]

Well, didn't do any water changes for a full week, but still not any nitrate in the tank according to my test kit.


Starting to think my test kit is a bit dodgey??

 

[rabbut]

Could take a sample of water to the LFS for a test there to confirm your results Make shure they use a liquid kit though, for reasons I'm shure you know

All the best
Rabbut

 

[petertr]

Could take a sample of water to the LFS for a test there to confirm your results Make shure they use a liquid kit though, for reasons I'm shure you know

All the best
Rabbut

Might just do that.

I had an API kit, but I ran out of a couple of tests, so I bought some separated on ebay - ammonia, nitrite and nitrate.

The Nitrate has 3 liquids and a power - its a Waterlife kit