12 replies to this topic

[kristof]

Hi all,

I've been looking into making a denitrate tower using seachems denitrate media and was wondering if anyone has got any first hand experience using this product.From what I've read on the net, it seems that you can get some reasonable results using it in the correct manner (low flowrate) and it is not necessary to feed the desired bacteria as is needed in conventional off the shelf denitrators. Please dont think that im any sort of expert on this subject. All I'm trying to do is slow down the nitrate buildup in my tank and if it turns out that it only works as added traditional filtration then so be it. Nothing ventured, nothing gained.

Thanks
Chris

[Buccal]

Just give it a go.

I'll just cast my view..
These reactors don't rip out nitrates greatly, only very slightly very slowly.
A well balanced tank that's under stocked and loaded with plants all working harmoniously insinc is only in need of water changes extremely rarely,,, as the nitrate builds so slow.
So in this situation the reactor should be the missing link to virtually self sustain via the total loop ecological loop closed in a continual running fashion,,,,, or close to. (possibly no longer needing water changes)....

A tank that is well stocked that sees nitrates climb fast needing weekly or fortnightly water changes I don't think the reactors will make much of a dent to be honest.

But entering this avenue, you don't just buy the reactor and read instructions and follow suit then see if it works.
You must study about the beneficial bacteria species that inhabits these filters and take note of their optimum requirements.
Requirements like temp, water chemistry and so on.
At least give it the best chance.

Edited by Buccal, 02 January 2016 - 11:55 AM.

[Riggers]

Hi mate

I've used a small patio planter box and a small spray bar over the top of my 6ft tank, fill it with plants and viola, instant denitrifying I found that with a tank of over 200 tropheus I could push water changes to 4-5 weeks.

Good project but mate, let us know how it goes

[sydad]

There is an old saying to the effect that there is no such thing as a free meal, and this may well be applied to denitrators. To understand why I say this, it is necessary for me to explain, briefly, how they work.

 

In essence they utilise the ability of many bacteria to change their metabolism when environmental conditions change. The bacteria in question normally utilise oxygen in their environment to metabolise nutrients. For this reason they are described as aerobes, and many are normal inhabitants of healthy aquaria. There are in addition a number of species that may become involved in denitrators that are seldom or never encountered in aquaria; this is probably an irrelevancy, but I just wish to make the point that the introduction of any new "system" will inevitably lead to changes in more ways than may be anticipated.

 

The aerobic bacteria I have mentioned have the capability to also survive, and successfully, when their oxygen source is for some reason cut off. They may then be labelled as facultatively anaerobic. The change in their metabolism requires that they utilise other energy sources to replace the lost oxygen-based metabolism. Aerobic bacteria that cannot utilise other energy sources are described as obligate aerobes for obvious reasons.

 

Returning to the facultative anaerobes: one of the nutrient sources many can use is the nitrate ion. The problem is that this can be considered an incomplete food (not quite correct, but near enough to explain why the following events happen).

Since the nitrate is "incomplete" as a food, and consequent energy source, it is necessary for an aquarist wishing to make use of the nitrate reduction process, to provide the missing "food". This can be done in a number of ways, but there are two traditional methods. The first is to provide an insoluble carbon source, and probably the commonest is cellulose. The other common addition is elemental sulphur, also virtually insoluble in water. The bacteria can access the necessary  additional nutrient from these two sources, and so use the nitrate also; in the process reducing it sequentially to ammonia, nitrite and finally, elemental nitrogen, which being a gas with very low water solubility is quickly lost to the atmosphere.

 

This is all great, and the purpose of the exercise is met.... the nitrate is removed! Trouble is that something else is added to the water (remember that nature abhors a vacuum), and all too often, that added something is more of a problem than the nitrate was. Anaerobic metabolism is at best complex, and the added substance/s can be as "simple" as dissolved organic carbon (this term covers a multitude of sins), or as soluble sulphur compounds (and few aquaria benefit from these).,Some or all of these constitute an additional load of dissolved elements within the aquarium, and many are actually just as, or more, toxic than the nitrate. This can sometimes not be evident for varying periods of time, and I have on numerous occasions been approached by other aquarists who have "suddenly" encountered problems further down the track. A recurring consideration is that solving, or finding a cause for those problems is inevitably difficult.

 

Consider: nitrates are relatively low in toxicity, and really quite simple to quantify. Admittedly in poorly buffered aquaria, where they exist as nitric acid, they can cause considerable and sudden devastation if allowed to build up. But the fact is that simple water changes easily eliminate any perceived or actual problems. Obviously in heavily planted aquaria, most nitrates will be utilised by the plants (or the ammonia that eventually becomes nitrate will be used even more rapidly).

 

On the other hand, the aquarium fitted with a denitrator, which a hopeful aquarist thinks will eliminate a known possible problem, may well be denied the benefit of a water change until there is a untoward event, the cause of which may not be readily detectable.

 

Syd.

[sandgroper]

I use Denitrate filters on 2 of my heavily stocked tanks and i love them. Mine are the Aqua Medic 1000 type fed with deniballs. The mistake people make is that they think that they can get away with out doing hardly any water changes. This isn't the case you still need to do regular water changes. What they do is allow you to keep a heavily stocked busy tank with out doing extra water changes and maintaining a fairly constant low level nitrate reading. If you don't do regular water changes the nitrates will slowly rise over time and problems will arise. They are handy to when you go away on holidays and miss one or two water changes, as they slow down the climbing nitrates. With out the feeding they would be fairly ineffective i would think but give it a go you never, never know, if you don't give it a go, go, go.

[bigjohnnofish]

never used a denitrator but a mate used to swear by them.. instead of a weekly water change he stretched it to 3 weeks.... but his 397s bred and he also bred 260's briefly before selling up... plus a few other species.... quite successful using denitrators on all of his tanks but was expensive.... i'd prefer the water change path to be honest

 

what are the best nitrate consuming plants one can have in their tank syd ?

[Buccal]

I think with the conversion that denitrators does into other toxins that's worse or as bad actually occurs or builds up at a massively slower rate than what nitrate takes to climb,,,, so coupled with what Sandgroper mentioned (the odd periodical water change) would keep the end processed products at a minimum and not have any negative impact.

For the process to effect fish as Syd explained is all very real (he's obviously very advanced in the science fields), but one would have to be one of those slob aquarists that never water changes and maybe have two large denitrators on a smallish tank packed with fish and maybe 1.5 - 2.5 years later.

For what they cost, and the effort it takes to water change fortnightly,,, it's really just trying to cut out something that's nothing much anyway,,,,,,,, Unless your one of those obsessive aquarists fixated on "NO NITRATES".
So my thoughts are same as Johnno's.

Also don't forget all those elements and carbonates and all the goodies that come out of new water that keeps water chemistry in balance and at its best,

Common watercress or Lebanese watercress (miniature), are biggest nutrient consumers.
Faster growing species consume nutrient faster.
Secondly, to double nutrient consumption, is to often cut back mature leaf growth by 80% down to node growths, to allow a rapid come back growth which requires a lot of nutrients to regenerate.
Watercress is grows at rocket speeds and re-generates like a middle age Italian mans flavor saver,,,, .

[kristof]

Thankyou all for replying to this topic.
As you can see from some comments (Riggers) and other comments I've read on other forums, some people are getting quite significant results using this product. The other main factor for me thinking of using it is because unlike most denitrators there is no mention on having to feed the bacteria with an added food source. Therefore, I'm assuming that the potential of harmful byproducts is significantly reduced and why some on the net call it a "safe" method. This is where I get a bit lost. If you are growing the same bacteria that breaks down the nitrates: A.why dont you have to give it additional food source and B.shouldn't it still be able to create the unwanted byproducts if not operating correctly.
Basically, all you need to do (according to seachem) is use it as a media in a canister filter and slow down the flowrate to approx 100 lph.
Please also understand that I'm not trying to eliminate water changes, it would be nice if it turns out that I can stretch them out to two weeks or so. Im on holidays at the moment with too much time on my hands so im just trying to expand my knowledge and maybe try something a bit different.
Thanks
Chris

[Delapool]

Out of interest how long have people used these products for in tanks? I've seen heaps of threads reporting success but it just struck me that I haven't seen much on the length of time. I've always wondered if these products eventually gunk up. Craig.

Edited by Delapool, 03 January 2016 - 12:43 PM.

[sandgroper]

I've been using them for about 5 years now and have tweaked them a little to reduce them clogging up, once a year they get a good clean out and some more Deniballs are added. I wouldn't be with out them now.

[bigjohnnofish]

watercress a floating plants or does it need a medium  to grow in.... and whos got some ???

[Terry]

Watercress can be obtained at most pond shops and Bunnings, it is more suited to ponds than aquariums.

 

The only chemical that I use is methylene blue apart from that my fish shed is chemical free, weekly water changes keep the aquariums healthy and the fish breeding. The new water is pumped from a 20,000 ltr pond which is then topped up from a 4,000 ltr water ageing tank. The pond is filtered with one ton of Zeolite which has not been touched for about 9 years (bacteria cleans it for me) the pond has lots of algae in it and I like to see algae on the walls of the aquariums, sometimes I clean the front glass. Algae cleans water the same way that watercress does.

 

Nice input Syd, always a wealth of information.

 

Cheers Terry

[Buccal]

When it comes to plant filters you need to know exactly what plant type your using first, then design your plant filter sump.
Watercress normaly floats but it really depends on the way your edible water celery (leb watercress) actually grows.
It will want to sink and carry on at the start but as soon as it takes and finds posture it levels out.
Definetely no media needed, and don't consider any media, just don't do it, as its like substrate in a fish tank that's to thick collection waiste that becomes a nitrate and gram-negative bacteria factory.
For watercress which I have a fair bit of experience with, the water depth is absolute optimum at 200mm deep.
This allows for about 80mm of stem base tufting, weaving and stitching,,,,, then another 120mm for the fibrous hungry roots to project and dangle downwards.
The water will pass underneath stem tufts and travel through roots.
The roots won't only extract nutrients, but beneficial bacteria will also establish in great numbers on this vast surface area of roots.
Always try to make filter as narrow as possible to be as long as possible, which directs the main water flow through the majority of the plants roots.
If you say start out with 5x cres lumps,,, then place pairs of bricks evenly spaced standing upright along the sump using 5x pair lots.
This way once water is flowing, the cres lumps will hold up in place against brick pairs.

I found easiest and cheapest way to build these is treated rough sawn pine sleepers, cheap pond liner and star pickets to hold sleepers together.
Make the filter 300mm deep for a 200mm water level.
Woodvale fish n lily farm sell large quantity.