Water Changes...Unnecessary?

[Coryloach]

The reports stated, rainbow trout and cutthroat trout fry are adversely affected, and in some cases can die, after exposure for 30 days to as little as 1.1-7.6 mg N03 - N/L.

Read the last paragraph of the study I posted #70. From all quoted studies only one found such low levels to be toxic, the one you are referring to. See the data for all the rest which determined toxicity levels in the hundreds and thousands on different freshwater fish and even majority of tested invertebrates, although I didn't quote that data.

The connection could be the extremely low hardness(<40 mg CaCO3/l) of the water used in that study. Some studies certainly point that nitrate toxicity decreases as hardness increases and the composition of the ionic content of the water plays a role in nitrate toxicity levels.

However, the low values in this study is the exception and not the norm for majority of the species studied. I'd like to see way more data supporting those low nitrate toxicity levels, than the one and only I could find so far...What I would like is actually to read the entire study myself as some studies are not isolating nitrate and other water parameters could have been in play, as I pointed earlier elevated nitrite is rather common....Nitrite is also known to be more toxic in water with lower hardness, unlike ammonia. Generally nitrite and nitrate are less toxic in water with higher hardness. Ammonia is the opposite.

Also, it is probably important to note that nitrate in its original form is not toxic to fish. It becomes toxic as it is converted to nitrite after it has entered the fish's system. In other words, the side effects of elevated nitrates and nitrites would have the same physiological effect on fish for the most part.. So when a study is done on NO3 toxicity, I think it is extremely important to make sure the NO2 does not become elevated as well....Otherwise I think it renders the study useless. Also, these studies tend to test NO2 weekly, although they'd monitor NO3 several times a day, and even with that rare testing of the more toxic nitrite, they still find elevated levels in the high nitrate groups, the few times they tested for it....

 

[RD.]

However, the low values in this study is the exception and not the norm for majority of the species studied

And in this hobby, there will always be exceptions. That was my point from the get go. The majority of species studied, is but a teeny tiny drop in the bucket when one considers the vast number of species of fish kept in captivity. The fact that even a few species are susceptible, out of the very few studied thus far, ought to be enough to make everyone realize that there may be other species that are just as susceptible to nitrates (at whatever life stages) as rainbow trout, and cutthroat trout. Wouldn't that seem logical, and be the most objective manner to approach this? Not ignore it, because we are lacking in studies involving several hundred ornamental species?

 

[squint]

What do you think would be the tropical fish most sensitive to nitrate? If it's not too expensive I can buy one and see how much nitrate it can withstand.

Even if some tropical species were just as sensitive, adult salmonids can withstand quite a bit (around 6,000 mg/L for 96 hours). Does that value justify a <40 ppm guideline?

 

[RD.]

With zero being the constant in nature that seems like the best goal one can have. My personal guideline is the same as most natural bodies of water, as close to zero as possible.

 

[OnceLoyal]

People on this forum will throw stones at me for this, but I do think many on here over emphasize wc. When tap has higher nitrates than tank is just one example.

Ponds that are not fed via spring or other source never change water. The water evaps and replenishment comes from rain or run off. To be honest in the past I only truely used mass wc for aid in growth (phermones). This is not including any major cleaning and stirring up the sand from time to time. Obviously it would be time for a nice wc. Hell, to be honest I never really tested water after my tanks were well established unless I added something new. Looking at build up of minerals could be another thought, but in some ways it is the opposite to me. Some may need replacing through a wc.

I am not saying wc isnt important. I am just saying if you got so busy and your well established and well set up tank (planted anyway) went for a month or longer without a wc. Have no fear fellow fish friends. You and your tank will be just fine. (Not including the overstocked and overstuffed tanks). I recall when I was younger and ran 4 tanks for many years there were many times I went a couple months without wc. Fish were always healthy and vibrant. Water was always clean and clear. But I must say when I did a huge cleaning and wc the water was invisible after a few hours. Man I loved those setups!! All smaller tanks. 2 55s and 2 33L under the 55s. Redbellies in one 55 and community in the other. Wolf in 33 and black p in the other 33. Glorious

Throw the stones

 

[RD.]

I haven't tested my water parameters in over a decade, maybe longer, but I do large water changes as often as possible.

Think of a fish tank as a toilet bowl - which would you rather be swimming in? A freshly flushed toilet, or one full of piss, and other nasty waste by-products.

This convo just went from mildly entertaining, to stupid.

RD out

 

[skjl47]

People on this forum will throw stones at me for this, but I do think many on here over emphasize wc. When tap has higher nitrates than tank is just one example.

Ponds that are not fed via spring or other source never change water. The water evaps and replenishment comes from rain or run off. To be honest in the past I only truely used mass wc for aid in growth (phermones). This is not including any major cleaning and stirring up the sand from time to time. Obviously it would be time for a nice wc. Hell, to be honest I never really tested water after my tanks were well established unless I added something new. Looking at build up of minerals could be another thought, but in some ways it is the opposite to me. Some may need replacing through a wc.

I am not saying wc isnt important. I am just saying if you got so busy and your well established and well set up tank (planted anyway) went for a month or longer without a wc. Have no fear fellow fish friends. You and your tank will be just fine. (Not including the overstocked and overstuffed tanks). I recall when I was younger and ran 4 tanks for many years there were many times I went a couple months without wc. Fish were always healthy and vibrant. Water was always clean and clear. But I must say when I did a huge cleaning and wc the water was invisible after a few hours. Man I loved those setups!! All smaller tanks. 2 55s and 2 33L under the 55s. Redbellies in one 55 and community in the other. Wolf in 33 and black p in the other 33. Glorious

Throw the stones

Hello; Simple thing is you are wrong. I started back around 1959 when WC was a yet to be learned practice. Home test kits were a ways off in the future.
The nice thing, so far at least, is we each get to turn our tanks any way we wish. Those who do not want to do WC can go that way.

My experience after several years of just topping off a closed system was that the WC was a big step in the right direction.

The farm pond analogy is poor. I live in a rural area. About twenty of my neighbors on the east are black angus cattle. It is my take that those who keep cattle would like a pond or stream with an input of fresh water. They make do with ponds. Those closed system ponds get pretty rank in the summer.

Go in peace.

 

[Coryloach]

And in this hobby, there will always be exceptions.

I could not find the entire Grabda et al. (1974) study you are referring to but here is what other scientists say about it.....

Quote:

The only indication that relatively low concentrations of nitrate may be harmful to fish comes from Grabda et al. (1974), who found that rainbow trout exposed to 22.0-26.4 mg NOf 1-1 displayed increased blood levels of ferrihaemoglobin, dam-age to the peripheral blood and haematopoietic centres, and liver damage. However, their data was not definitive since nitrite was not measured in the experiments, and these effects may have been caused by nitrite accumula-
tion (Colt and Armstrong 1981).

Nitrate Toxicity to Penaeus Monodon Protozoea (PDF Download Available). Available from: https://www.researchgate.net/publication/226360338_Nitrate_Toxicity_to_Penaeus_Monodon_Protozoea [accessed Apr 24 2018].

 

[RD.]

I knew that I would somehow be drawn back into this ........

The reports stated, rainbow trout and cutthroat trout fry are adversely affected, and in some cases can die, after exposure for 30 days to as little as 1.1-7.6 mg N03 - N/L.



So at 4.8 ppm nitrates, what do you reckon the nitrite accumulation would be?

And that was only 30 days ......

Honestly, I really don't care how many papers are presented, or colors of fonts anyone uses - when someone makes a claim as fact, and those facts cannot be backed up with proper data, they become almost meaningless to me. It's not my position to have to prove anything here, I wasn't the one that originally posted about nitrate toxicity. As stated, far too many variables involved, and far too many species. Far be it for me to argue with the likes of Edward J. Noga, because of some so called facts presented by a couple members of a fish forum.

Good luck fellas.

 

[exodus1500]

I'm not even going to bother reading all of this, I just read whats on this page. What every everything else has been said, RD is right.

The vast majority of my fish are wild caught South American fish. When the nitrates hit 40, I can tell without testing the tank. Small little fin tags here and their, an ever so slight cloud to the eyes. I watch my fish VERY closely. People can post anything they want about Nitrates being fine for fish. Maybe some fish can take it better than others. But that doesnt mean its ok. But us humans don't make the best decisions for ourselves and our health, so I dont expect the vast majority to take care of their fish as well as they can either.