Cycling questions

[Rtc/tsn]

Dumb question especially coming from someone who’s kept fish for over a year now but can someone explain to me the chemical process of a tank undergoing the cycling process. I’ve never been able to understand too much when researching it so maybe some of you can dumb it down for me a bit. I don’t really know much if anything about what happens while a tank is cycling.

 

[tlindsey]

Dumb question especially coming from someone who’s kept fish for over a year now but can someone explain to me the chemical process of a tank undergoing the cycling process. I’ve never been able to understand too much when researching it so maybe some of you can dumb it down for me a bit. I don’t really know much if anything about what happens while a tank is cycling.

I don't know if this helps.

Conversion of Ammonia to Nitrite then to Nitrate.

 

[Rtc/tsn]

I don't know if this helps.

Conversion of Ammonia to Nitrite then to Nitrate.

Not sure if that was a link gone wrong but honestly it opened a bit for me, I’ve never known the order of which they convert(?) what’s the difference between nitrite and nitrate.

edit: I copied and pasted and now doing some research hopefully I’m not up all night tryna figure this out

 

[esoxlucius]

To dumb it down into the very basics. A new tank, whether you go the "fish in" route, or just add ammonia/fish food/shrimp, whatever, will start to produce ammonia as the first part of the cycle. Ammonia is extremely toxic, even in very low ppm's.

Fortunately there is a bacteria, nitrosomnas, which eats the ammonia rendering it safe, but....a by product of this process is nitrite, which is just as toxic as ammonia, so we're back to square one.

However, we have another friendly bacteria, nitrobacter, which eats the nitrite and the end product of this is nitrate. Nitrate is far less toxic than the other two, but long term, it can cause problems. Nitrate and fish is like cigarette smoke and humans. It's a slow burner.

This is where the cycle ends in our aquariums. We don't have another friendly bacteria to eat the nitrate*. So what do we do now? Well the nitrate, over time, will gradually rise, quickly if you are overstocked and/or feed heavily. Slowly if you are understocked and feed lightly. It's what we call "bio load".

This is where water changes come into the equation. We must dilute that forever rising nitrate. And that's as dumbed down as I can put it.

*There are other bacteria that do indeed eat nitrate, but not in the usually oxygen rich closed loop environment that our aquarium set ups offer. This method of nitrate reduction is very complex.

 

[Rtc/tsn]

To dumb it down into the very basics. A new tank, whether you go the "fish in" route, or just add ammonia/fish food/shrimp, whatever, will start to produce ammonia as the first part of the cycle. Ammonia is extremely toxic, even in very low ppm's.

Fortunately there is a bacteria, nitrosomnas, which eats the ammonia rendering it safe, but....a by product of this process is nitrite, which is just as toxic as ammonia, so we're back to square one.

However, we have another friendly bacteria, nitrobacter, which eats the nitrite and the end product of this is nitrate. Nitrate is far less toxic than the other two, but long term, it can cause problems. Nitrate and fish is like cigarette smoke and humans. It's a slow burner.

This is where the cycle ends in our aquariums. We don't have another friendly bacteria to eat the nitrate*. So what do we do now? Well the nitrate, over time, will gradually rise, quickly if you are overstocked and/or feed heavily. Slowly if you are understocked and feed lightly. It's what we call "bio load".

This is where water changes come into the equation. We must dilute that forever rising nitrate. And that's as dumbed down as I can put it.

*There are other bacteria that do indeed eat nitrate, but not in the usually oxygen rich closed loop environment that our aquarium set ups offer. This method of nitrate reduction is very complex.

Exactly what I was wanting thank you so much for this information. Since I posted this thread I’ve been researching and nothing makes as much sense to me as this does for some reason. While doing my own research I’ve came across denitrification, does this come into play in the aquarium setting or would it have to be induced into action. Would a biologically sufficient and sustainable denitrifying process be helpful to reduce the need of a water change.
Edit: I didn’t read the very last sentence, would denitrifying be the same as nitrate/nitrite reduction?

 

[esoxlucius]

Exactly what I was wanting thank you so much for this information. Since I posted this thread I’ve been researching and nothing makes as much sense to me as this does for some reason. While doing my own research I’ve came across denitrification, does this come into play in the aquarium setting or would it have to be induced into action. Would a biologically sufficient and sustainable denitrifying process be helpful to reduce the need of a water change.

Denitrification is the "complex process" I was referring to. It's more for the advanced hobbyist to play around with.

But no, even reducing your nitrates considerably with denitrification still doesn't mean you can do away with water changes.

You still need to replenish your system with clean fresh water to maintain your levels of trace minerals that are in said clean water, plus the build up of fish hormones and such need to be diluted to.

There will never be a closed loop aquarium system that doesn't need water changes once in a while. Heavily planted tanks and extremely minimal stocking can mean those water changes are few and far between, but sooner or later you'll still need to do a water change.

 

[Rtc/tsn]

Denitrification is the "complex process" I was referring to. It's more for the advanced hobbyist to play around with.

But no, even reducing your nitrates considerably with denitrification still doesn't mean you can do away with water changes.

You still need to replenish your system with clean fresh water to maintain your levels of trace minerals that are in said clean water, plus the build up of fish hormones and such need to be diluted to.

There will never be a closed loop aquarium system that doesn't need water changes once in a while. Heavily planted tanks and extremely minimal stocking can mean those water changes are few and far between, but sooner or later you'll still need to do a water change.

Not saying this cause I’m tryna get out of water changes but in theory would it be possible to create a self sustaining simulated aquatic environment. Just came to mind and had to delete a good 2 paragraphs cause I didn’t notice that rain and groundwater along with other components would be nature’s way of a water change. This brings the question how exactly is it possible that oscars live nitrate free in the wild ( this was bright up in a separate thread) if it’s an ongoing cycle where they’re constantly producing their counterparts then how could it be possible for a water system in nature to have such equilibrium

 

[esoxlucius]

Not saying this cause I’m tryna get out of water changes but in theory would it be possible to create a self sustaining simulated aquatic environment. Just came to mind and had to delete a good 2 paragraphs cause I didn’t notice that rain and groundwater along with other components would be nature’s way of a water change. This brings the question how exactly is it possible that oscars live nitrate free in the wild ( this was bright up in a separate thread) if it’s an ongoing cycle where they’re constantly producing their counterparts then how could it be possible for a water system in nature to have such equilibrium

Because in nature the relative stocking levels, compared to a cramped aquarium, are miniscule. And the water bodies in question are often billions and billions of gallons of forever turning over water. So the build up of nitrate is zero.

Now transfer that concept over to your closed loop tiny aquarium, with loads of fish, and no means of regular fresh turnover of water and......I'm sure you're getting the picture.

 

[Rtc/tsn]

Because in nature the relative stocking levels, compared to a cramped aquarium, are miniscule. And the water bodies in question are often billions and billions of gallons of forever turning over water. So the build up of nitrate is zero.

Now transfer that concept over to your closed loop tiny aquarium, with loads of fish, and no means of regular fresh turnover of water and......I'm sure you're getting the picture.

Yea I understand that. I feel like a nerd saying all these big words ?. Thank you for the information. I could go into a bunch of what if scenarios but imma leave that for the morning. I’m definitely not the advanced aquarist but do look to get some information on the more complex cycles such as denitrifying and go all in with other bacteria species (are the classified by species) and what roles they do or potentially could playin the aquarium setting. Don’t know why but my simple brain is so fascinated by this.

 

[duanes]

In nature plants are large consumers of nitrate.
But in pristine natural settings the ratio of plants to animals is staggeringly high, the forests that surround the waters where our fish come from use nitrate almost the moment it is produced.
To help mitigate nitrate in my tanks (beside the heavy water change schedule 30%-40% every other day) I use sump/refugiums filled with aquatic, semi aquatic, and terrestrial plants.
Below is the planted 125 gal refrugium I use to help eat nitrate on a 180 gal tank with fish.

It uses vallisneria, water lilies, and now, mangrove trees to help consume nitrate.
Below, a dozen mangrove saplings are growing in the refugium.

But the 180 is also heavily planted with val, hydrophilla and terrestrial plants growing on the waters surface.

Yet.... when you compare these to nature, it is nothing compared to the plants in natural tropical habitat, and the reason a heavy regime of water changes is needed to hold nitrate down.

Above the foliage surrounding a tributary of the Rio Magdalena in Colombia, where many of our fish come from.