Nitrate Myth?

[Nont]

So I used to be on many of the fish forums. There, whenever someone make a thread about their diseased fish, everyone who answer would blame on Nitrate or filter. However, from my reading on UKAPS and my fishkeeping experiences it seems like Nitrate have little to do with diseases and filters aren’t even nescessary.
I have plantless 200l tank with 30 tetras and a discus with only a sponge filter, Nitrate is always 70ppm or more because of well water and I don’t seems to have any problem with it, and i haven’t had any fish died in a year now after switching from canister to sponge filter.

So my question is the following;
1. Is Nitrate causing diseases in fish just a myth?
2. Can Nitrate over 10ppm cause health effect on human? have to question because I drink well water of my place (about 50ppm) for my whole life and my family doesn’t believe in RO filter :/
3. Is aquarium filter even necessary assuming there are proper O2 levels in the water.

 

[fredi]

I think it depends on the fish
My tapwater is often as high as 40ppm

 

[john6]

My tap water is always 40ppm (when I've tested it) so I don't think it's harmful to humans.
I used to keep fish in my tap water before I got RO unit and I can't recall many if any deaths.

 

[John q]

. Is Nitrate causing diseases in fish just a myth?

Yep it's a myth. Often quoted as the smoking gun.. ammonia or nitrite is usually the culprit.

2. Can Nitrate over 10ppm cause health effect on human?

Possibly yes, however the scientific evidence suggests not. The Risk Assessment Information System

Drinking Water Nitrate and Human Health: An Updated Review

Nitrate levels in our water resources have increased in many areas of the world largely due to applications of inorganic fertilizer and animal manure in agricultural areas. The regulatory limit for nitrate in public drinking water supplies was set to ...

www.ncbi.nlm.nih.gov

3. Is aquarium filter even necessary assuming there are proper O2 levels in the water.

If we had sufficient circulation by other means, high plant mass and a light fish load then yes, filters are unnecessary, .

 

[Happi]

1. Is Nitrate causing diseases in fish just a myth?

its not a myth, the fishes needs to be exposed to it for period of time before they start to decline. there are many article out there that can explain it in much more details, google is your friend.

2. Can Nitrate over 10ppm cause health effect on human? have to question because I drink well water of my place (about 50ppm) for my whole life and my family doesn’t believe in RO filter :/

seems risky according to this

3. Is aquarium filter even necessary assuming there are proper O2 levels in the water.

long as there are plants in the tank and water is moving with a pump, there will be plenty of O2. I use pump or filter only for flow without any media.

 

[MichaelJ]

If we had sufficient circulation by other means, high plant mass and a light fish load then yes, filters are unnecessary,

Agreed.. I consider my filters serving the propose of providing circulation and mechanical filtration. The high plant mass in my tanks and mature substrate should provide all the bio filtration I will ever need in these tanks, but circulation needs to be excellent. In a small tank with a high plant mass an internal filter with a sponge will be sufficient.

2. Can Nitrate over 10ppm cause health effect on human? have to question because I drink well water of my place (about 50ppm) for my whole life and my family doesn’t believe in RO filter :/

The EPA limit in the US is 10 ppm. Drinking water with high nitrate is not good for you - especially for infants or if there are underlying health issues. Thats not to say that you will get health issues, but it certainly increases the risk. I would try an avoid drinking water containing 50 ppm if Nitrates for an extended period of time:

Nitrate in Drinking Water - MN Dept. of Health

www.health.state.mn.us

Cheers,
Michael

 

[sparkyweasel]

I wondered why the USA had a much lower limit than many other countries. It appears to be because of measuring it differently and the actual limit is about the same if measured in the same way.
"The maximum contaminant level (MCL) for nitrate in public drinking water supplies in the United States (U.S.) is 10 mg/L as nitrate-nitrogen (NO3-N). This concentration is approximately equivalent to the World Health Organization (WHO) guideline of 50 mg/L as NO3 or 11.3 mg/L NO3-N (multiply NO3 mg/L by 0.2258)."
hth

 

[xZaiox]

I wondered why the USA had a much lower limit than many other countries. It appears to be because of measuring it differently and the actual limit is about the same if measured in the same way.
"The maximum contaminant level (MCL) for nitrate in public drinking water supplies in the United States (U.S.) is 10 mg/L as nitrate-nitrogen (NO3-N). This concentration is approximately equivalent to the World Health Organization (WHO) guideline of 50 mg/L as NO3 or 11.3 mg/L NO3-N (multiply NO3 mg/L by 0.2258)."

Glad you commented this Sparky - I was starting to worry reading through this

 

[MichaelJ]

This concentration is approximately equivalent to the World Health Organization (WHO) guideline of 50 mg/L

Good catch @sparkyweasel !... I didn't know - and oddly enough the EPA usually do not say Nitrate from NO3-N just Nitrate or just NO3 - my local water report from the city where I live also only says Nitrate:

Contaminant (Date, if sampled in previous year)	EPA’s Ideal Goal(MCLG)	EPA’s Limit(MCL)	Highest Average or Highest Single Test Result	Range of Detected Test Results	Violation	Typical Sources
Nitrate	10 ppm	10.4 ppm	3.7 ppm	2.00 - 3.70 ppm	NO	Runoff from fertilizer use; Leaching from septic tanks, sewage; Erosion of natural deposits.

Cheers,
Michael

 

[Simon Cole]

Nitrate disease in aquarium fish has been wildly mythologised, and misinformation on nitrate toxicity is often simply <conjecture dressed up as wisdom>. There is evidence that it is a real phenomenon, but most people fail to appreciate the <observed> concentrations that result in nitrate toxicity and the fish species concerned. One <school of thought> is that it is unlikely to be observed in aquariums with nitrate concentrations below 440 ppm. That is not an unreasonable position to take, because few aquarists keep fish species that are definitively sensitive to nitrate toxicity.

I would be a bit careful when googling for a magic bullet answer. There will probably be a few papers that evidence nitrate toxicity in certain fish species at the lower aquarium concentration levels, but in my opinion the burden of proof actually leans towards this not being a practical problem to the vast majority of aquariums. Also, many people now have a vested interest in proving, rather than disproving the impact of nitrate toxicity in fish, and possibly this is why there is so much discourse online. They all go quiet when you ask about empirical evidence and the null hypothesis.

Drinking water quality is a far more persuasive argument because it involves nitrate toxicity in humans, and there has been a bit of debate over "blue tongue syndrome in babies" dragging on over the years. The WHO did a rather shoddy job investigating the covid outbreak, and I have always felt that their guidelines on water quality are a bit optimistic, so I do think it could be worth your time reading the literature and adopting a precautionary principle.