Another "cycling the tank" question

[TinaPax-Peeks]

My 20g tank is cycling...no fish, newly planted and filter plants in place.

ammonia is gone, nitrites are at 4 and nitrates are at 40ppm.  

My question is: do I need to do a partial water change to lower the nitrates?

This is a part I don't understand from all the "how to cycle your tank" videos... Should I do water changes during this process? At what point? 

Edited June 16 by TinaPax-Peeks
Correct spell-check

[Tlindsey]

On 6/16/2024 at 7:13 AM, TinaPax-Peeks said:

My 20g tank is cycling...no fish, newly planted and filter plants in place.

ammonia is gone, nitrates are at 4 and nitrates are at 40ppm.  

My question is: do I need to do a partial water change to lower the nitrates?

This is a part I don't understand from all the "how to cycle your tank" videos... Should I do water changes during this process? At what point? 

Yes partial water changes will lower the Nitrate. You will have to be consistent with the water changes and test the aquarium water as your fish and plants grow.   

[TinaPax-Peeks]

On 6/16/2024 at 7:21 AM, Tlindsey said:

Yes partial water changes will lower the Nitrate. You will have to be consistent with the water changes and test the aquarium water as your fish and plants grow.   

Thanks. For some reason, my brain wants to separate the initial cycling process from the ongoing maintenance process. 

[Tlindsey]

On 6/16/2024 at 7:27 AM, TinaPax-Peeks said:

Thanks. For some reason, my brain wants to separate the initial cycling process from the ongoing maintenance process. 

Once you do the water changes for awhile it gets easy. The plants will help a bit. 

[doktor zhivago]

40ppm is fine, actually great for the plants. I usually don't water change until mine get around 80-100ppm. I try and keep my tanks around 40ppm for the plants. 

I wouldn't mess with the water until the nitrites start dropping. There is some controversy about nitrite levels getting too high and stalling the cycle but I'm not sure. If they stay less than 5ppm it should be fine. 

[TinaPax-Peeks]

On 6/16/2024 at 8:26 AM, doktor zhivago said:

40ppm is fine, actually great for the plants. I usually don't water change until mine get around 80-100ppm. I try and keep my tanks around 40ppm for the plants. 

I wouldn't mess with the water until the nitrites start dropping. There is some controversy about nitrite levels getting too high and stalling the cycle but I'm not sure. If they stay less than 5ppm it should be fine. 

That touches on another question that I think is answered with "depends" -- what level of nitrates is acceptable/desirable?  I guess "it depends" on whether the tank is planted or not and maybe on what fish it is stocked with.... whether the goal is a "natural ecosystem" or not...so many factors it boggles my brain.

I understand that nitrates aren't as dangerous to fish as nitrites but I am not clear on how much is too much. I hear some say to water change at 25ppm or 40ppm or some higher number. 

[doktor zhivago]

On 6/16/2024 at 7:42 AM, TinaPax-Peeks said:

That touches on another question that I think is answered with "depends" -- what level of nitrates is acceptable/desirable?  I guess "it depends" on whether the tank is planted or not and maybe on what fish it is stocked with.... whether the goal is a "natural ecosystem" or not...so many factors it boggles my brain.

I understand that nitrates aren't as dangerous to fish as nitrites but I am not clear on how much is too much. I hear some say to water change at 25ppm or 40ppm or some higher number. 

fish can tolerate nitrates into the hundreds of ppm, not ideal but survivable

plants need nitrates to thrive

keeping mine under 100ppm but above 40ppm seems to work well for both my fishies and my plants. 

[Tony s]

@TinaPax-Peeks yes, agree completely with @doktor zhivago. But didn’t want to muddy the water, again. Nitrates for fish aren’t really directly poisonous either. Think of it as being in a smoke filled room. You can survive in it, bit gets more difficult as levels get higher. Causes long term damage, not direct poisoning. Which is why we try to keep it down 

African cichlid keepers that can’t keep plants often get to the lower hundreds without ill effect. And plants need at least 20ppm to survive well. Also depends on the species. Discus and rams like very low levels. Almost 0 for a good discus tank 

[daggaz]

I'm surprised there's no section on cycling on the guides page. 

[Tony s]

On 6/16/2024 at 9:47 AM, daggaz said:

I'm surprised there's no section on cycling on the guides page. 

You’re right, but boy do we spend a lot of time on the forum🤣

[TinaPax-Peeks]

On 6/16/2024 at 9:47 AM, daggaz said:

I'm surprised there's no section on cycling on the guides page. 

Sorry, I didn't even think to check there. Or, perhaps I didn't know where it is and it didn't pop up in my search. Mea culpa. 

Edited June 16 by TinaPax-Peeks
Added content

[daggaz]

Why say sorry? There's nothing there to help people with cycling.   Which is weird, because it's a fundamental topic in the field. 

[Tony s]

On 6/16/2024 at 10:30 AM, daggaz said:

Which is weird, because it's a fundamental topic in the field

Yeah. But oh so many variables. Fish in. Fish out. Ghost feeding. With meat or fish food. Adding ammonia. Adding plants. Adding bacteria or not. It can go on and on. Sometimes it’s easier to talk through it. It seems everybody’s situation is slightly different. 
@TinaPax-Peeks never apologize for asking questions. We like to help. Almost as much as we like fish in some cases. 😂

[TinaPax-Peeks]

On 6/16/2024 at 10:30 AM, daggaz said:

Why say sorry? There's nothing there to help people with cycling.   Which is weird, because it's a fundamental topic in the field. 

Oh, I thought you were implying there was one and I couldn't find it! Lol

On 6/16/2024 at 10:39 AM, Tony s said:

Yeah. But oh so many variables. Fish in. Fish out. Ghost feeding. With meat or fish food. Adding ammonia. Adding plants. Adding bacteria or not. It can go on and on. Sometimes it’s easier to talk through it. It seems everybody’s situation is slightly different. 
@TinaPax-Peeks never apologize for asking questions. We like to help. Almost as much as we like fish in some cases. 😂

Thanks! :-). And, yes, even after multiple videos watched multiple times, I still get confused about how to apply the info to my situation.  I am very thankful for the opportunity to benefit from the collective knowledge of this forum!

[Rube_Goldfish]

You don't have any fish in the tank, so I don't see any reason to change any water. Let the nitrite-eating bacteria population grow. Moreover, you've got emersed-growing plants that I remember from your other thread, so once they really get going those nitrates will likely go down on their own.

[johnnyxxl]

I did a fishless cycle with plants and inadvertently some snails that hitchhiked.  I didn't do any water changes just kept monitoring the water did a big change 50 percent before adding the first fish like a week before 

[daggaz]

On 6/16/2024 at 2:26 PM, doktor zhivago said:

There is some controversy about nitrite levels getting too high and stalling the cycle but I'm not sure. If they stay less than 5ppm it should be fine. 

Is it controversial?  There seems to be a wealth of related information in various journals, indicating that increased free ammonia concentrations can have an inhibitory effect on nitrite oxidizing bacteria.  Here is one in particular that happens to not be behind a paywall (hurray!)   Mechanistic understanding of the NOB suppression by free ammonia inhibition in continuous flow aerobic granulation bioreactors - ScienceDirect

This paper comes from the waste-water treatment industry, where they actually don't want to produce all those nitrates.  A secondary finding is that low oxygen saturation will also inhibit NOB.  

Now what exactly are the upper limits, or the optimal ppms to shoot for, is probably not easily shown due to the wide biodiversity of bacterial organisms and the various genomes and thus competing metabolisms they represent.  It's gonna vary somewhat from tank to tank, especially if you compare an inert substrate to an aquasoil to a natural dirted tank, for example.  But still, I am curious.  

Edited June 17 by daggaz
Doh. Just realized you were talking about nitrite and not ammonia. Hmm.

[daggaz]

Here's an interesting one on nitrite.  They go from 200 ppm inlet flow concentration of nitrite to 500 ppm, but its into a big reactor bed that can convert everything under both conditions, so no info on overloading, unfortunately.  They do however confirm the r/K competition hypothesis between nitrospira and nitrobacter populations, and show that under heavier nitrite loads, the nitrobacter dominates, nitrobacter being the one that can metabolize nitrite faster, and nitrospira being specialized in dealing with very low concentrations (somehow).   Effect of nitrite concentration on the distribution and competition of nitrite-oxidizing bacteria in nitratation reactor systems and their kinetic characteristics - ScienceDirect

[TinaPax-Peeks]

On 6/17/2024 at 5:16 AM, daggaz said:

Here's an interesting one on nitrite. 

Very interesting articles. I don't suppose there are any articles address nitrate levels?  

[daggaz]

Google scholar is your friend.  Works just like Google, tho it helps to use more technical terms if you can.  Searching "nitrate toxicity aquatic" gives me the following review (a paper that builds a larger overview of many other papers published in the field stretching over some relevant time span, often done by a prominent researcher in the field):

https://www.sciencedirect.com/science/article/abs/pii/S0045653504009993

Research indicates that nitrate concentrations over 10ppm can harm freshwater fish, invertebrates, and amphibians over long-term exposures, however the toxicity is greatly affected by the cationic composition of the water (exactly how is behind the pay wall, unfortunately).  Nitrate toxicity occurs primarily thru reactions that disable oxygen binding molecules like hemoglobin, however because adsorption into the gills is greatly reduced by the aqueous environment, fish and other organisms can tolerate 5x or more higher nitrate concentrations than terrestrial organisms. 

[Tony s]

On 6/17/2024 at 2:26 PM, daggaz said:

Nitrate toxicity occurs primarily thru reactions that disable oxygen binding molecules like hemoglobin, however because adsorption into the gills is greatly reduced by the aqueous environment, fish and other organisms can tolerate 5x

I believe I saw a guppy fry study where they were surviving into 300ppm. Not living per say, but not dying either

[TinaPax-Peeks]

On 6/17/2024 at 3:10 PM, Tony s said:

I believe I saw a guppy fry study where they were surviving into 300ppm. Not living per say, but not dying either

Which is the more difficult thing to quantify--  the continuum between existing-but-miserable to healthy.  I might be able to eat a diet of junk food and not die; but, am I healthy?  Most of these studies are aimed to see how commercial fish farms can get the most fish to market for the least cost. How bad can the pond water be without killing the fish? Others are looking at ecosystems in need of clean up.

Back in the mid-80's, I was in a college program for marine research. We participated in a research study of the Chesapeake Bay with Woods Hole Geological Survey. We collected many samples of the water of Bay and charted the nitrite/nitrate levels. We also were mapping the mixing of the freshwater with the ocean.  Anyway, one question was how industrial waste being dumped into the bay affected nitrites/nitrates and thus the health/life in the Bay. (I didn't continue in that career pursuit because I get very seasick.)

That either makes me sound more knowledgeable than I am or reveals how limited my knowledge is in this stuff. Lol

My thoughts on the issue of what level of nitrates I am comfortable allowing in my tank are 40ppm.  Now, as I stock my tank and observe the fish, I may decide it can go a bit higher or I may decide to keep it lower. Right now, at this stage, I just don't feel comfortable with 60 or 80 ppm nitrates.  Yes, I hope the plants will extend the time between water changes. That is my main purpose in having them.  

[daggaz]

I'd say it was the continuum between living healthy and death, but yes. Results may vary. 

I doubt 40 ppm is even a noticeable effect without rigorous statistical control, but who knows.  And for all we know, the captive bred species may have already developed resistance to increased nitrate levels.  Who knows? 

If your fish are thriving and healthy and living well into their breeding age, nobody can shame you for causing them harm.  Not everything in the environment is good for you.  Perfect health doesn't exist. 

[Tony s]

On 6/17/2024 at 9:34 PM, TinaPax-Peeks said:

Which is the more difficult thing to quantify--  the continuum between existing-but-miserable to healthy.  I might be able to eat a diet of junk food and not die; but, am I healthy?

I was just fascinated with the study. especially with fry, who are far more sensitive to water conditions. seems like that would not be possible. and yet there it is. for me I get nervous around 40ppm. but then I had a lot of smokers around as a kid🤣

[TinaPax-Peeks]

On 6/17/2024 at 9:50 PM, Tony s said:

I was just fascinated with the study. especially with fry, who are far more sensitive to water conditions. seems like that would not be possible. and yet there it is. for me I get nervous around 40ppm. but then I had a lot of smokers around as a kid🤣

It is interesting that the fry could survive that high of nitrates. I wonder if it is similar to how some marine life come into brackish or fresh water to lay their eggs? Or, adaptation to polluted conditions? Or....??