# Nitrogen Cycle in a planted tank with new filter



## ltsai (5 Jul 2013)

Hi,

My fishless planted tank was setup in Mar using coco peat mixed with granular fertilizer, meant for household plants and topped with aqua soil. 

Tank is moderately planted with java fern, moss, hair grass, glosso, e. tenellus and c. helferi with pressurized co2. 

I had since removed my internal filter with no filter medium that was used for flow, and just bought a new canister filter. 

I do perform weekly water change too. 

I remembered reading somewhere on this forum that it typically takes about 6-8 weeks to get it established from a new planted tank since almost everything in the tank acts as a huge biological filter. 

Since I had the tank from Mar but with a new filter medium, do I need to wait a few more weeks to get some established in the filter?

Thanks!


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## Alastair (5 Jul 2013)

Id say yes you would be best waiting a few weeks for bacteria to colonise the filter.  
Id introduce fish very slowly to start with and see if anyone you know with an aquarium has some seeded media they could give you to put in the filter to speed it up

Sent from my GT-I9505 using Tapatalk 2


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## plantbrain (6 Jul 2013)

I add fish and shrimp at 3 weeks. I do 2-3x a week 50-80% water changes, there's no NH4 anywhere.
Plants mop what little there might be, there's no "cycle". Never seen one in my tanks after 20+ years. 

I suppose if you added a lot of fish, had very few plants etc, then perhaps.


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## ltsai (9 Jul 2013)

Thanks Tom. Shall wait a few more weeks then.


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## sciencefiction (9 Jul 2013)

When I do a fishless cycle with ammonia the cycle takes about 3 weeks to go through the ammonia/nitrite stage, with plants or no plants, I've done it both ways. So presuming ammonia equals fish bioload, that's really the minimum period to wait for the filter to establish and the plants to take off to a level you'd like.   If you don't want sick fish, white spot outbreaks, unexplained deaths, etc..then wait a few weeks before adding anything and then stock slowly regardless.


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## dw1305 (9 Jul 2013)

Hi all,


sciencefiction said:


> So presuming ammonia equals fish bioload, that's really the minimum period to wait for the filter to establish and the plants to take off to a level you'd like.


I like to let the tank establish, and add the fish a few at a time, but there isn't a lag period with plants, they will utilise any available nitrogen straight away. A plant with the "aerial advantage", like an emergent or a floater, will show an almost instant growth response to nutrients. 


sciencefiction said:


> When I do a fishless cycle with ammonia the cycle takes about 3 weeks to go through the ammonia/nitrite stage, with plants or no plants, I've done it both ways


Our tanks are never really cycled in the way that an un-planted tank would be, we are nothing like so reliant on the filter bacteria, because we have a much larger range of sites for nitrification (root rhizosphere etc.) and plant / microbe systems have much greater capacity than microbial systems on their own. 

Biological filtration is really all about oxygen, and again that is the advantage of plants, they produce oxygen during the photo-period. If we don't have any plants (or at night) we need a large gas exchange surface, ideally from a trickle filter, but also from high flow rates or direct aeration (which works mainly by increasing the surface area of the tank).

cheers Darrel


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## ltsai (9 Jul 2013)

dw1305 said:


> I like to let the tank establish, and add the fish a few at a time, but there isn't a lag period with plants, they will utilise any available nitrogen straight away.


 
Nitrogen? But aren't we dosing EI in excess that are we already have abundance of them?


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## dw1305 (9 Jul 2013)

Hi all,


ltsai said:


> But aren't we dosing EI in excess that are we already have abundance of them?


I'm not dosing EI, but even if we were, the levels of nitrogen that some plants could actually utilise would be higher than the level dosed. If you have a look through the scientific literature you'll find a lot of use of (Water Hyacinth) _Eichornia crassipes _and (Nile Cabbage) _Pistia stratiotes_ in waste water treatment, mainly because they thrive in eutrophic conditions and show a linear growth curve for nutrients up to really high levels of nitrogen. I'd have to look up the exact figures, but it will be linear up to at least 400ppm N (~1600ppm N), and certainly _Eichornia_ will grow successfully in "raw sewage".
This is an aquaculture reference, from: International Journal of Phytoremediation Volume 14, Issue 3, 2012.


> Water hyacinth (_Eichhornia crassipes_) and water lettuce (_Pistia stratiotes_) were analyzed to determine their effectiveness in aquaculture wastewater treatment in Malaysia. Wastewater from fish farm in Semanggol Perak, Malaysia was sampled and the parameters determined included, the pH, turbidity, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), phosphate (PO43−), nitrate (NO3−), nitrite (NO2−), ammonia (NH3), and total kjedahl nitrogen (TKN)..... Percentage reduction of turbidity for _Eichhornia crassipes_ were 85.26% and 87.05% while _Pistia stratiote_s were 92.70% and 93.69% respectively. Similar reductions were observed in COD, TKN, NO3−, NH3, and PO43−. The capability of these plants in removing nutrients was established from the study.


cheers Darrel


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## sciencefiction (9 Jul 2013)

> I like to let the tank establish, and add the fish a few at a time, but there isn't a lag period with plants, they will utilise any available nitrogen straight away. A plant with the "aerial advantage", like an emergent or a floater, will show an almost instant growth response to nutrients.


 
They will utilize nutritients only if there's sufficient CO2 for them to grow fast. And if there's a shortage of certain other nutritients besides nitrogen, then there'll be a problem with growth too, and the ammonia will not be taken up as fast as one wants. So for one to be sure the tank is in "health" condition, regardless of method used, one better waits and see if the tank is growing well for a few weeks using the current method. And yes, emergent plants and floaters are the "insurance" in case the submerged plants are suffering from lack of CO2 which in majority of planted tanks seems to be the limitation as it's hard to get it right. If one is experienced, then you maybe able to add fish straight away in a CO2 and nutritient supplemented planted system, unlike unplanted tanks in which you've got to wait a few weeks at least.




> Our tanks are never really cycled in the way that an un-planted tank would be, we are nothing like so reliant on the filter bacteria, because we have a much larger range of sites for nitrification (root rhizosphere etc.) and plant / microbe systems have much greater capacity than microbial systems on their own.


 
And what's the difference? That besides establishing a microbial system in substrate/filters, one also has plants to help with the take up of ammonia/nitrites/nitrates?


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## dw1305 (9 Jul 2013)

Hi all,


sciencefiction said:


> So for one to be sure the tank is in "health" condition, regardless of method used, one better waits and see if the tank is growing well for a few weeks using the current method.


I'd recommend leaving the tank for a "growing in" period, definitely "_good things come to those who wait_" (from this link) <Accuracy of test kits? | Page 2 | UK Aquatic Plant Society>.


sciencefiction said:


> And if there's a shortage of certain other nutritients besides nitrogen, then there'll be a problem with growth too, and the ammonia will not be taken up as fast as one wants.


 It is certainly possible, but unlikely in most circumstances. Plants are extremely efficient at scavenging available fixed nitrogen, it is a scarce resource in nearly all natural ecosystems, and they have evolved complex systems to exploit sudden abundance.


sciencefiction said:


> And what's the difference? That besides establishing a microbial system in substrate/filters, one also has plants to help with the take up of ammonia/nitrites/nitrates?


 The difference is that plant/microbe systems are many times more effective and stable than microbial systems. It isn't a trivial difference, they really are "chalk and cheese". 

I've never had an un-planted tank system, and I can't imagine l ever will. Plants are a KISS solution to all biological filtration problems. If you keep Mbuna or Koi you just have the plants in a separate container, if you are worried about oxygen depletion at night, you have a sump with a reversed lighting regime etc. 

cheers Darrel


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