Plants And Nitrate

[elmo666]

Hi. I'll try to compact what could be a complex question. I have a planted 250 litre discus set-up, pressurize co2 on timer with twin t5 plant tubes also timed. Filtration is eheim pro350. Just, (since Friday) started using r/o with its own pre-filters and separate 3 pod HMA filter for water to mix with it. Minerals are put back using tropic marin pro discus mineral. I went down the r/o route as despite 50% water changes weekly I couldn't rid my tank of high nitrates.
Now, to get to the point, how much nitrate can be utilized by plants in a fairly well planted tank, say 80% of base covered and many reaching surface of 700mm deep tank? I have a mix of hygrophilia, greens and red, varios swords, aponogetans and anubas (please excuse any poor spelling and lack of accuracy on types, I don't keep the labels. It was suggested in another thread of mine (nitrate reactor) that plants should reduce nitrate to zero. Is this possible with the feeding regime young discus require??

 

[elmo666]

Forgot to mention, I feed aqua grow nutrafeed and a powdered preparation, Lush Max from the internet, I rotate them weekly to try and give a balanced feed. Water changes at 50 litres 3x weekly, filter cleaned fortnightly.

 

[rms]

Plants help reduce nitrate, but not by much. Fast growing plants have the best impact and elodea is a popular choice. If yours are very high then the plants won't have much of an impact though.
 
You could try buying filter media that helps with anaerobic colonies that consume nitrate. There are several products out there, but it does take some time for the colonies to grow. A couple months. I've heard some pretty amazing results though and it is proven to work very well in reducing nitrate.
 
How come they're so high if you're using RO water? Are you mixing it with tap water as well? What's the nitrate level in your tap water? 
 
I'm not familiar with Lush Max, but that might be increasing your nitrates as well. I'm not entirely sure though on that, but worth looking into.

 

[SO19Firearms]

You don't want to be reducing Nitrate to zero in a planted tank. Adding about 30ppm weekly should be enough, maybe some more if you're lighting and CO2 requires it.

 

[elmo666]

Sorry if my post wasn't clear. I wasn't suggesting for a second zero nitrates was a good idea, and I was questioning the comment made in another thread that a well planted tank could reduce nitrates to such a low level, after all they're constantly being produced, and over a lengthy period of "lights out" when no photosynthesis is taking place to utilize them. I've recently put Purigen into my filter. The r/o hasn't had long to make a significant impact as I'm mixing it with pre-filtered tap water, and sadly the nitrates are 30+ppm in that. I've ordered a nitrate reactor which uses Seachem Denitrate, which as you've said, goes anaerobic at its core, helping denitrification, so hopefully that should help. I'd use elodea, but doesn't that favour lower temps? Hence a favourite for goldfish bowls

 

[TwoTankAmin]

You do realize that both of the fertilizers you are using contain nitrogen? Now I could not see what form the N is in from their sites, but this might provide a hint or two. It is for SeaChem's Nitrogen which I use.
 

Flourish Nitrogen
Product Description
Flourish Nitrogen™ is a concentrated (15,000 mg/L) blend of nitrogen sources. It provides nitrogen in both the nitrate form and the plant-preferred ammonium form. However, no free ammonia is released because the ammonium in Flourish Nitrogen™ is complexed and unavailable until utilized by the plants. Flourish Nitrogen™ also provides nitrate for those plants that can readily utilize nitrate as well. For maximum benefit use with Flourish Phosphorus™ and Flourish Potassium™..........
 
Because one-half of the nitrogen in Flourish Nitrogen™ is from nitrate you can get a reasonable estimate of nitrogen levels by doubling a nitrate reading, or, you can use Seachem’s MultiTest: Total Nitrogen™ (coming soon!) to accurately measure total nitrogen while distinguishing between nitrate, ammonia and organic nitrogen.

from http/www.seachem.com/Products/product_pages/FlourishNitrogen.html
 
 
So you may actually be adding nitrate to your tank and may not realize it. This is what I think is happening. Your tank as described should not have a nitrate problem. Nor does it have anything to do with 0 nitrate being a good or bad idea. And your post was unclear because you failed to mention the ferts you are dosing not because of any misunderstanding in terms of nitrate levels. In well planted, higher light co2 added tanks it is common for there to be 0 nitrates and adding them become necessary.
 
But, plants consume ammonium at a faster rate than bacteria can consume ammonia. When the plants are processing any part of total ammonia, they do not produce any nitrite or nitrate. There can be only two sources of nitrate in your tank- tap water and things you are adding. With your plant load you have minimal bacteria and gence are creating minmal amounts of nitrate.
 
Next, photosynthesis has nothing to do with ammonium and/or nitrate uptake by plants. They will take it in during both light and dark hours. I recently made the mistake of concluding they only took in nutrients during daylight and discovered I was incorrect about this. Some plants may take in less during dark hours, but they are still taking in nutrients. Photosynthesis itself only occurs during daylight hours. But most plants prefer ammonium to nitrate. So from this angle your plants are working hard to minimize the ammonia left for nitrifying bacteria which in turn reduces potential nitrate being created by the bacteria.

 

[sawickib]

Using fast growing house plants in your filters like golden pothos, bamboo, or spider plants helps lower nitrates a lot, i think pothos works the best. This is the thread showing kinda what i did not a walk through though.

 

[SO19Firearms]

Soooo many pills and potions to reduce Nitrate.......somebody's getting rich.

 

[elmo666]

A bit confused about the reference to seachem ferts, I don't use them. Apologise in advance if that was used as an example. Should I stop dosing with ferts? If I did where would the other trace elements and minerals needed by the plants come from?
Sadly no chance of terrestrial plants being used as there is a miniscule amount of access on my tank which is covered by my lights.

 

[rms]

I'd be very interested to know how you get on with the Purigen, lots of mixed views. Can you post an update in a month?

 

[KirkyArcher]

The reference to Seachem Nitrogen I believe was to indicate that the "Nitrogen" element that is also contained within your two fertilisers (AquaGro NutraFeed & Lush Max) may be in the Nitrate form, that may be the reason your nitrates are so problematic.

 

[TwoTankAmin]

TY KA- I thought I had made that point crystal clear.
 
I am amazed by what people put into their tanks without really having a good idea what they are doing or what they may actually be adding.
 
One can find ferts in a ton of different forms. For example here is my list:
 
Tropica Plant Nutrition (Now rebranded as Plant Growth Premium): "Properties Premium Fertiliser contains the most important nutrients for healthy and sustained aquarium plant growth. Premium Fertiliser does not however contain nitrogen (N) or phosphorus (P)."
SeaChem: Nitrogen, Potassium, Phosphorus, Iron and Excel
Dry Ferts: Potassium Nitrate, Plantex CSM+B, MnSO4 and FeDTPA 10% (see this recipe http/www.barrreport.com/showthread.php/7134-How-to-make-DIY-Tropica-Plant-Nutrition-%28or-how-to-make-the-Good-****%29 )
 
Different tanks get different additions of the above.

 

 

[elmo666]

Right fellas, good input. Lets lay my cards on the table.
Purigen in its 4th week. Noticeable improvement in water clarity in 1st week. Didn't notice any change in nitrates, but understand that's a slow process brought about by reductions in nitrogenous waste and subsequently nitrates.
I'm fairly new to the higher tech side of plants and water chemistry so thanks for bearing with me. I understood that higher light levels and co2 went hand in hand with a regular regime of dosing ferts and plenty of water changes. Tho common sense may suggest that if you could get the balance just right the water changes would be more to replenish minerals and less of a nitrate controlling measure, meaning less needed.I'm happy to take on board any opinions put forward. I'm concerned about to much of a swing in any direction on my parameters, after all its the sensitivity of the discus and rams that is my primary concern.
I can see the sense in the r/o approach, starting with a blank canvas so to speak. What I wasn't happy about was then using raw tap water with it to replace "lost minerals" whilst also putting back all manner of undesirable pollutants. That's why I opted to use a 3 stage hma pre filter for this.
So, getting back to the ferts, are any available that are nitrate free? Or is it moreover a matter of not using them? I've read about macro and trace elements only being used, are these a better option?

 

[l_l_l]

Well not sure why the guy above said a well planted tank doesn't do much difference to nitrates...
Probably never had a fully planted tank himself..
 
From my side,
All of my planted tanks have been showing 0 nitrates and had to start dosing it manually because they eat the Ammonia away even before it goes to nitrates!
TTA is right about most people not even knowing what happens when they add ferts to their tanks!

 

[elmo666]

Thanks for your input, the plot thickens lol. Lots of food for thought.
just installed a new nitrate reactor. No experience of these at all. The instructions state the flow rate must not exceed 250lph. But it doesn't state a minimum or optimum rate. Because of the head of my set-up, 800mm, the small pump supplied is only giving 30-40lph. Now, does any one know if this is sufficient to 'feed' the anaerobic bacteria and allow denitrification to take place?