Curious case of no Nitrates? Expert opinion needed.

[The.WishMaster]

Hello Experts.

I am in the hobby since 2 years now and have two tanks. My main tank is what I would like to discuss today. I have a community tank that is around 180 liters. Its a planted tank and I have changed the substrate once, after a year.
I am running two filters in the tank, one built in filter that does 600L/Hr and one external canister filter that is suitable for 500L+ tanks. Both filters have a lot of biological media and I have hardscape as well in the aquarium.
Its also a heavily stocked tank with 50+ fish of 14+ species and amano shrimps too.

The problem or the weird case: Since the very beginning of my tank, I have not had ANY nitrate readings. They are usually 0 or less than 0.05. I don't do frequent water changes, maybe once every 3 months or so. I have professional testing kit and I have never been able to read any nitrates in my tests. Today I took my aquarium water for testing at a local fish shop and after doing the same test 10 times, from two different kits they couldn't find any nitrates.
I am trying to figure out if its normal or not? How is it even possible? Did I achieve a miracle? I did build my tank getting inspired and educated by MD fish tank videos.

I am wondering if this is causing any harm to my tank or not? Weird thing is this that the first year my aquarium plants were thriving and after a year they started to wilt away. That is when I changed my substrate again and put a fresh layer of root tabs and aqua soil on top of nutrient based soil and capped it with sand. Since the wilt started happening and till now, my root plants are not surviving well, leaves are becoming crispy and dark/black and non of the floating plants are surviving. I just bought a bunch of fresh plants and planted root tabs beside the roots and also added liquid fertilizer too. I do it once a month anyways but I will increase it to once a week now.

I am not sure if lack of nitrates is causing my plants to wilt or something else. The test results showed that I have everything perfectly balanced in terms of Micro and Macro nutrients just my Nitrates are 0.

Could someone offer me some advice or share a similar example? What should I be doing to keep my plants healthy? My pH is 7.8 and water temp is (24-27 degrees) it fluctuates in summers. I know the pH is high but I had a whole year of full lush growth on the same pH before it went side ways.

Looking forward to your help!
<3

 

[seedoubleyou]

Over filtered?

 

[The.WishMaster]

Filter bacteria doesn't remove nitrates, just ammonia and nitrites right ?

 

[Wookii]

What fertiliser are you dosing and how much?

 

[The.WishMaster]

Colombo flora grow recommended dosage for 180L tank. I mean where is the fish waste going ? Its a high stocked aquarium.

 

[Wookii]

Colombo flora grow recommended dosage for 180L tank.

Flora grow is not a complete fertilizer - if I'm looking at the correct product it contains no nitrates or phosphates. Nitrates and Phosphates are 'macro' nutrients - they (along with potassium) are required by plants in much higher quantities than other nutrients. Without them, your plants will slowly die, particularly once any nutrients contained in the soil gradually get depleted.

You need to switch to a complete fertiliser - something like APT Complete/EI might be available in your market (or better still on a tank that size, mix your own from dry salts).

I mean where is the fish waste going ? Its a high stocked aquarium.

The plants are consuming the relatively small amount being produced - it's about the only thing keeping your plants alive, but it's nowhere near enough as your deteriorating plant health and nitrate measurements are showing.

 

[Hanuman]

Doing a quick search on that product here is what I found:

Flora-Grow is a liquid plant fertilizer, which contains all the necessary minerals and trace elements such as Iron (Fe), Magnesium (mg), Potassium (K), Cobalt(Co)

I am not sure what they imply by "all the necessary minerals" however there is no mention of one of the most important ones which is nitrogen. So I am not sure what's in that product but maybe by using a more reputable brand you could see some better results. Perhaps Tropica or you could even make yours or as mentioned by Wookii get some APT which works well and is widely used and available now.

 

[dw1305]

Hi all,

I am trying to figure out if its normal or not? How is it even possible?

You can have very low nitrate (NO3-) levels in a planted tank.

Filter bacteria doesn't remove nitrates, just ammonia and nitrites right ?

Yes, you can only remove nitrates by four different pathways:

• <"water changes">,
• <"anaerobic denitrification">,
• <"selective nitrate anion exchange resins"> or
• <"plants">.

Plants are very efficient at taking up all forms of fixed nitrogen, <"much more efficient"> than most of the Aquarium based literature acknowledges. The <"spare" oxygen from photosynthesis"> ensures optimal microbial nitrification and the plants do the rest.

I am wondering if this is causing any harm to my tank or not? Weird thing is this that the first year my aquarium plants were thriving and after a year they started to wilt away. That is when I changed my substrate again and put a fresh layer of root tabs and aqua soil on top of nutrient based soil and capped it with sand. Since the wilt started happening and till now, my root plants are not surviving well, leaves are becoming crispy and dark/black and non of the floating plants are surviving. I just bought a bunch of fresh plants and planted root tabs beside the roots and also added liquid fertilizer too. I do it once a month anyways but I will increase it to once a week now.

I think you've answered your own question there, at least one of the essential nutrients for plant growth is <"missing, or very deficient,"> and severely limiting plant growth. A floating plant has access to atmospheric CO2, so growth problems will be <"mineral nutrition related">.

Colombo flora grow recommended dosage for 180L tank. I mean where is the fish waste going ? Its a high stocked aquarium.

The fish waste is going into the plants and making plant tissue. When you remove plant material you remove those nutrients. <"Plants require a lot of nitrogen">, to make the proteins involved in photosynthesis, to the extent that you can use the growth and leaf colour of a floating plant <"as an index of nitrogen content">.

Flora grow is not a complete fertilizer - if I'm looking at the correct product it contains no nitrates or phosphates. Nitrates and Phosphates are 'macro' nutrients - they (along with potassium) are required by plants in much higher quantities that other nutrients. Without them, your plants will slowly die, particularly once any nutrients contained in the soil gradually get depleted.

I am not sure what they imply by "all the necessary minerals" however there is no mention of one of the most important ones which is nitrogen

You need to switch to a complete fertiliser - something like APT Complete/EI might be available in your market

<"That one">. I use a <"commercial fertiliser mix"> (designed for hydroponics), but APT complete etc is fine.

cheers Darrel

 

[X3NiTH]

Today I took my aquarium water for testing at a local fish shop and after doing the same test 10 times, from two different kits they couldn't find any nitrates.

Did/do you ever test for the presence of the precursor Nitrogen compounds, either Ammonia or Nitrite?

 

[The.WishMaster]

Did/do you ever test for the presence of the precursor Nitrogen compounds, either Ammonia or Nitrite?

Yes, during the cycling phase and then after I installed new substrate and restarted the tank. Both times Ammonia and Nitrites were there but never again. The LFS also tested for those. All were 0.0.

Hi all,

You can have very low nitrate (NO3-) levels in a planted tank.

Yes, you can only remove nitrates by four different pathways:

• <"water changes">,
• <"anaerobic denitrification">,
• <"selective nitrate anion exchange resins"> or
• <"plants">.

Plants are very efficient at taking up all forms of fixed nitrogen, <"much more efficient"> than most of the Aquarium based literature acknowledges. The <"spare" oxygen from photosynthesis"> ensures optimal microbial nitrification and the plants do the rest.

I think you've answered your own question there, at least one of the essential nutrients for plant growth is <"missing, or very deficient,"> and severely limiting plant growth. A floating plant has access to atmospheric CO2, so growth problems will be <"mineral nutrition related">.

The fish waste is going into the plants and making plant tissue. When you remove plant material you remove those nutrients. <"Plants require a lot of nitrogen">, to make the proteins involved in photosynthesis, to the extent that you can use the growth and leaf colour of a floating plant <"as an index of nitrogen content">.



<"That one">. I use a <"commercial fertiliser mix"> (designed for hydroponics), but APT complete etc is fine.

cheers Darrel

and to All who replied. I have a special version / variant of Colombo Flora Plant Fertilizer that comes with Nitrates and Phosphates in it.

Should I increase the dosage or the frequency? Will that help? Is fertilizer harmful for the fishes?

I don't want to do too many water changes as I designed it to be a low maintenance tank. Also, should I consider installing CO2 again? Would it be better for plants considering current conditions?

 

[X3NiTH]

I have a special version / variant of Colombo Flora Plant Fertilizer that comes with Nitrates and Phosphates in it.

Colombo Flora Grow Pro

Is there a nutrient percentage list on the back of the bottle and if so could you post a pic? Here’s hoping Nitrate and Phosphate aren’t token amounts.

Should I increase the dosage or the frequency?

I would increase the overall weekly dose but splitting that to also increase the frequency of dosing to every other day so that you reduce the chance of shortfall of any one element.

The only way you can determine if plants are consuming all the available Nitrogen is to dose a known value of Nitrate (significant enough to be measured, say 10ppm) and then test at regular intervals (?hourly) to discover the uptake rate of the plants (or de Nitrification via the substrate).

Is fertilizer harmful for the fishes?

Providing any Nitrogen being dosed is already present in the bottle as Nitrate and not from Urea or Ammonia then most definately not at the amount you are dosing, not even if you multiplied that dose by 10.

Also, should I consider installing CO2 again?

I wouldn’t, not until you start getting positive healthy growth in your floating plants as from your description they are suffering from lack of Nutrition already whilst having access to 421ppm of CO2 from the atmosphere.

 

[Wookii]

I don't want to do too many water changes

With that quantity of fish, regular weekly water changes should be considered essential for their health and well being.

If you want to get away with fewer water changes of longer duration between them, then you really need to maintain a very lightly stocked tank.

 

[MichaelJ]

With that quantity of fish, regular weekly water changes should be considered essential for their health and well being.

If you want to get away with fewer water changes of longer duration between them, then you really need to maintain a very lightly stocked tank.

Agreed.... or add more plants.

Cheers,
Michael

 

[seedoubleyou]

Filter bacteria doesn't remove nitrates, just ammonia and nitrites right ?

Sorry mate I’ve as much knowledge on the chemistry stuff as I do about what my wife fancies for dinner.
Normally I’d advise a tuxedo urchin, but they’re only for reef aquariums.

 

[MichaelJ]

Filter bacteria doesn't remove nitrates, just ammonia and nitrites right ?

Anaerobic bacteria and plants will consume nitrate.

Cheers,
Michael

 

[Hanuman]

Yes but there ain’t any anaerobic bacteria in filters unless one believes in pond guru’s magical bio media

 

[MichaelJ]

Yes but there ain’t any anaerobic bacteria in filters unless one believes in pond guru’s magical bio media

Haha… I didn’t say filter, but should have said substrate.

Cheers,
Michael.

 

[The.WishMaster]

@X3NiTH here you go mate.

 

[Hufsa]

@X3NiTH here you go mate. View attachment 208105

Not the most ideal picture but I have taken the liberty to write it down and convert the "as oxide" numbers. Not entirely sure what they mean with the Nitrogen description, so have left that as is.

Percentage by weight:
0.36% Nitrogen total (N) Nitrate nitrogen
~0.053% PO4
~0.59% K
~0.19% Mg

0.062% Iron (Fe DTPA)
0.02% Manganese (Mn EDTA)
0.003% Boron (B EDTA)
0.001% Zinc (Zn EDTA)
0.002% Copper (Cu EDTA)
0.005% Molybdenum (Mo EDTA)
0.0004% Cobalt (Co EDTA)

 

[tam]

Mines the same, never measurable, I don't think it's that odd in a planted tank. It's why so many people with planted tanks add ferts with nitrate, where as fish only people tend to be horrified at the idea as they are always trying to reduce it.

Plants will also uptake ammonia before your filter bacteria have a chance to process it into nitrate so it may never get that far anyway.

Going well to start and then tailing off is often because tanks start with an active substrate that gets depleted. A lot of MD tanks are quite short term set up, so you see the initial boom from the good substrate and no so much longer a year or two down the line tanks.

I need to add more nitrate to mine, even my duckweed looks sad. I'm surprised it's not already been mentioned, but definately search the forum for 'duckweed index' for a guide to working out when your plants need ferts.