signs of a cycled tank?

[Paul B]

Aha but water changes do affect the cycle. By removing ammonia, you are removing the food for the bacteria that you are trying to grow. By removing nitrate you are also removing food for nitrobacters. By removing bacteria you are pushing the cycle backwards and if you put all of the rock and water into a larger space you will also retard the cycle.
It is not only the relitive proportions that completes a cycle, it is sheer numbers of bacteria. It takes a certain amount of bacteria to process a given amount of wastes regardless of the proportions of ammonia, nitrate etc.
Paul

 

[MikeS]

Agreed with PaulB....

What is important to understand here is that the "cycle" is a constant, ongoing process in the tank, not simply a beginning point and ending point. Ammonia, nitrate, nitrite, and many other things are constantly being produced, consumed, transformed, recycled, bound up, stored, released, ect, ect by a very complex biological system hapenning in the tank. The goal really is threefold here....#1 to make sure the water is safe (not toxic) for livestock, #2 to keep an equilibrium in the tank through biological and/or mechanical means, and #3 to export toxins and pollutants in one form or another in a sufficiant quantity to keep the water habitable for our livestock.

MikeS

 

[ronj]

yeah, but doing the WC's are going to reduce the waste that has to be broken down...when the cycle is complete, they are going to dieoff anyway because there won't be anything left for them to feed on..you are going to do water changes when it is complete anyway, which is going to starve alot of them......if they are just going to dieback in numbers anyway, you only need enough to support the first inhabitant that you add!! as long as there are a little more than enough to complete the cycle, that is all you need for your first fish!!

 

[Sherman]

It is not only the relitive proportions that completes a cycle, it is sheer numbers of bacteria.

First, before anything else: Please read my comments as questions, not challenges. I appreciate the opportunity to learn, certainly! Especially from a man who's had a tank longer than I've been alive.

I'm interested in your statement here, Paul. Honestly, I'm having hard time grasping the theory. Are you suggesting that bacteria can't eat unless they're in mass quantities? That can't be the case, or a cycle would never start. If:

It takes a certain amount of bacteria to process a given amount of wastes regardless of the proportions of ammonia, nitrate etc.

... is true, why wouldn't it take less bacteria to process a lesser amount of waste, which is the result of a water change?

What's the difference between a decently matured (say... 3 years, just to pick a number out of a hat) tank, versus a brand new one, in regards to nutrients? The 3 year old tank has far less nutrients, and far less bacteria. As a tank first cycles, the swings are so extreme because of die off, but this die off becomes less and less, so the "cycle" is like a pendulum, slowly working it's way back and forth to an eventual "still" spot. Of course, as stated clearly, there is no true dead-center still spot. Add a fish, and you nudge the pendulum. Feed the fish, and likewise. Etc. My intent with heavy water changes during a cycle is to knock the edges off of that pendulum swing, and dampen it down toward center.

 

[MikeS]

The balance between availiable nutrients and bacteria/biological populations is in a constant state of flux...one will always be trying to catch up with the other...increased nutrients will cause bacterial populations to rise, bacteria will die off as available nutrients are limited, lower bacterial populations can cause a rise in nutrient levels again, ect, ect.....and the multitude of factors that play into the whole thing is huge...water changes, bioload, feeding regiment, export methods, recylcing, ect....really you never have a true equilibirum here at all, no matter how old the tank. Just about everything you do to your tank effects it in one form or another.....

MikeS

 

[Brenden]

I'm interested in your statement here, Paul. Honestly, I'm having hard time grasping the theory. Are you suggesting that bacteria can't eat unless they're in mass quantities? That can't be the case, or a cycle would never start. If:

What he is trying to say is not that bacteria needs mass quantities before it can eat but that it needs mass quantities to comsume the waste from the fish etc that you will be adding to the tank once the cycle is done. By reducing this "load" you are reducing the waste removal capabilities of your tank.

What's the difference between a decently matured (say... 3 years, just to pick a number out of a hat) tank, versus a brand new one, in regards to nutrients? The 3 year old tank has far less nutrients, and far less bacteria. As a tank first cycles, the swings are so extreme because of die off, but this die off becomes less and less, so the "cycle" is like a pendulum, slowly working it's way back and forth to an eventual "still" spot. Of course, as stated clearly, there is no true dead-center still spot. Add a fish, and you nudge the pendulum. Feed the fish, and likewise. Etc. My intent with heavy water changes during a cycle is to knock the edges off of that pendulum swing, and dampen it down toward center.

You want the pendulum to be swinging good when the first fish/load is put in the tank. You do not want it to be hardly swinging so it has to play catchup at the first introduction of waste.

 

[Meche]

I understood everything there was to understand about the nitrogen cycle... untill I read this thread :lol:

 

[zoo_keeper]

It's my understanding that you are not removing bacteria with water changes, since most are associated with the substrate and filters. If they were present in the water column in great quatities then UV sterilizers would cause a mini-cycle and I'm told they don't.

I do water changes during a cycle thinking that I'm not affecting the percentage of ammonia:nitrite:nitrate, only reducing all.

I got a mini-cycle when I added more bio-load to an established tank. I already had old substrate (20 yrs old), used sponges in my powerheads and established live rock. I added Bio-spira and an hour later tested no ammonia or nitrite, just 5mg/l nitrate and have never seen ammonia and nitrite again. I thought it was pretty amazing since the Bio-spira had ammonia in it.

 

[Brenden]

There is not a lot of bacteria in the water column. However when you do water changes you reduce their available food. They population depends on the amount of food/waste.

 

[Paul B]

Quote "What's the difference between a decently matured (say... 3 years, just to pick a number out of a hat) tank, versus a brand new one, in regards to nutrients? The 3 year old tank has far less nutrients, and far less bacteria."

If this were true, my 36 year old tank should have no bacteria. The three year old tank will have a higher fish load than the one year old tank therefore more bacteria. Also in an older tank there are uncountable organisms that are not bacteria that also add to the bioload. The gravel in my old tank is loaded with worms, amphipods, copepods etc. these also must be counted in bioload.
Also as the tank matures, bacteria do not automatically die when the cycle is "complete". They will continue to multiply as long as there are waste producing animals in the tank. Fish always excrete ammonia and it always has to be converted to nitrite which always has to be converted to nitrate. If the bacteria die off you will have an increase in either ammonia, nitrite or nitrate causing fish to die.
Bacteria are always increasing and to make it a little more complicated, there are not just three types of bacteria like we always mention in these discussions, there are thousands of types, some of which are better at utilizing wastes. Just because you may think a tank is cycled because of a test kit does not mean that it is cycled with a really efficient type of bacteria.
Bacteria help us by accident, they probably don't even like us. :badgrin:
They just happen to like to eat either ammonia, nitrite or nitrate and "their" wastes just happen to be not as toxic as the original ammonia that fish excrete. In the life of a tank the bacteria are always in competition with each other for space, and just like in the animal world, the strong survive. There are also a lot of other bacteria in our tanks that just take up space and don't help us at all. Thats for another discussion but I will say that all cycled tanks are not the same, we as aquarists and not scientists have a simplistic view of how this all happens but there are more variables at work here than you imagine, thats why so many people have so many problems even when they do the same thing.
Now your confused.
Paul

 

[Sherman]

You want the pendulum to be swinging good when the first fish/load is put in the tank. You do not want it to be hardly swinging so it has to play catchup at the first introduction of waste.

My understanding of the pendulum is this: There's die off, which feeds the bacteria. The bacteria multiply with such an abundant food source, but end up consuming all the food source, and the bacteria start dying off. All this new die off creates a new abundant food source (probably for a different kind of bacteria), and the new bacteria starts multiplying, yet end up consuming the new food source, dying off themselves... and now you see why it's called a cycle.

The pendulum is the die-off/multiplication factor, and I've always understood you want that swinging pendulum to be as stable as possible. Swings in die off and new bacteria growth aren't stable. I also recognize this as dynamic. When I added a foxface to my 2 year old tank, nitrates shot through the roof and I had many SPS lose color. The foxface eats 3 times as much as the rest of the tank combined, and he completely destroyed the tank's equilibrium. 4 months later, it's much more stable again, and my tank's chemistry and populations are certainly significantly different.

If this were true, my 36 year old tank should have no bacteria.

Interesting. Obviously, we know this isn't true.

The three year old tank will have a higher fish load than the one year old tank therefore more bacteria. Also in an older tank there are uncountable organisms that are not bacteria that also add to the bioload. The gravel in my old tank is loaded with worms, amphipods, copepods etc. these also must be counted in bioload.

Right! I was thinking of a 3 year old tank that still only had LR and sand. I had assumed a tank that hadn't been changed, except for chemistry. Sorry for the confusion. Do you think a brand new tank would have less bacteria than the exact same tank 3 years later?

Bacteria are always increasing and to make it a little more complicated, there are not just three types of bacteria like we always mention in these discussions, there are thousands of types, some of which are better at utilizing wastes.

Could you please post a comprehensive list? LOL

Just because you may think a tank is cycled because of a test kit does not mean that it is cycled with a really efficient type of bacteria.
Bacteria help us by accident, they probably don't even like us. They just happen to like to eat either ammonia, nitrite or nitrate and "their" wastes just happen to be not as toxic as the original ammonia that fish excrete. In the life of a tank the bacteria are always in competition with each other for space, and just like in the animal world, the strong survive.

No worries here, we're on the same page. I still see my tank maturing, after just over 2 years. (Do you remember back that far? ) And you always hear the generic guidelines like waiting one year for an anemone, and so on.

...but I will say that all cycled tanks are not the same, we as aquarists and not scientists have a simplistic view of how this all happens but there are more variables at work here than you imagine, thats why so many people have so many problems even when they do the same thing.,

One of my club members upgraded his tank a while back. He offered to pay/trade any other member for a piece of their LR and a scoop of sand. In the end, I think he got probably about 20-30 pieces (~50lbs) of rock and as many 1 cup scoops of sand for the new tank (standard 180g). I've always thought that was a great idea. Let 'em ALL fight it out for an ultimate cycle but a tank that has awesome potential diversity.

With my tank, a major portion of the rock came from another well-established (5+ years) tank's teardown. I also collected sand from probably a half dozen different tanks. The established rock and, IMO, the heavy water changes from the beginning led to one of the smallest cycles I've ever seen.

Are you saying that the bacteria population never decreases? I always understood there was a decent population spike in the middle of the initial cycle.

 

[syddakyd]

yea so i'll just get the test kit

 

[burning2nd]

it will really be eazyer that way,


were not really talkin about life here (i know some are and thats whats inportent) but where talking about $$-----> drain

 

[Paul B]

Quote Are you saying that the bacteria population never decreases? I always understood there was a decent population spike in the middle of the initial cycle.

The number of bacteria in a tank never decrease (Unless an antibiotic is used) but certain types of bacteria decrease to be replaced by other bacteria. Bacteria are very good at utilizing space and every milimeter will be populated by some type of bacteria. Most of these will be of no help for our purposes. We want to cultivate a good strain of bacteria that happen to like to convert ammonia to nitrite and nitrite to nitrate. They if we are lucky we can also get some anerobic bacteria to live in the same tank to convert the nitrate to something not too harmful like nitrogen gas. Of course some of those anerobic bacteria like to produce hydrogen sulfide which is much more harmful than the nitrogen. All bacteria are also affected by temperature, salinity, light, ozone, viruses and fungus.
I like to occasionally add bacteria from the sea because after a while you will have only a few types of bacteria in your tank. As I said, they are always in competition for food and space and the strong will survive leaving no room for other bacteria that may have beneficial qualities that we want.
After a few years the original thousand or so types of bacteria will be reduced to just a few types. If you add some fresh bacteria from the sea you will be adding some needed diversity. Of course, since this is not an exact science it is pot luck and you can't be sure of the exact types of bacteria you are adding but from experience I know this is beneficial as I do it all the time and have been for many years.
Have fun
Paul

 

[Paul B]

I guess that I should add that I am talking about a healthy aquarium.
I am not talking about disease causing bacteria which although are also in our tanks do increase and decrease depending on certain circumstances. If you overfeed or if something dies the water gets cloudy because there is no more room for the bacteria to multiply on the substrate and they will be forced to float in the water causing it to get cloudy. These will die when the food is removed.

 

[copepod]

http://www.cvreefers.org/v/CVR_members/Sherman/album67/

Great pics, I like your stand.

 

[Sherman]

Ha, thanks! It used to be a corner unit TV cabinet.

Paul, I definitely understand what you're saying about bacteria populations changing. I just really assumed that during the initial cycle there was so much more for them to eat that they were so much more prolific. What, in your mind, makes the difference between a tank "ready for corals" and not, in regards to maturity, not equipment. A tank is always cycling, but when do we call the initial algae bloom cycle "done." And what, specifically, has changed in a year to make one's tank ready even for anemones?

 

[Paul B]

Sherman, I think the time where a tank is ready for anemones or corals is an arbitrary point. I believe a tank gets better in time and the more diverse bacteria and other fauna, the better. All corals and anemones are different in the conditions they need and the overall health that you aquired them in. A healthy coral may have no trouble adapting to a new tank where an ailing coral may not live in a very mature healthy system. In short, there is no answer to your question.
As I said IMO there is no point where a tank is cycled. It continues forever as animal populations change and grow.
But in a new tank, even though you may get no ammonia or nitrite reading, you probably will when you add something because the number of bacteria are only enough to process whatever you used to cycle the tank in the first place. If you cycled the tank with a few mollies then there are enough bacteria (usefull bacteria) to remove wastes from a couple of mollies, not for a 6" anglefish. But if you gradually add animals the cycle will progress further until the bacteria run out of space whereas you will not be able to add anything and the tank will crash. Of course we strive to limit the number of creatures we keep so this does not happen.
Paul

 

[Paul B]

One more thing to get you a little more confused is that if you decrease the animal load or the feeding some of the beneficial (to us) bacteria will die. That does not leave empty space, it makes room for the bacteria that are there to eat the bacteria that just died. There are also bacteria that eat dead algae and diatoms. Everything that we ever put in our tanks was eaten by bacteria (or removed by water changes) If your water gets cloudy it just means that there is no more space for bacteria on objects and it is forced to occupy any floating debris that it finds.
Of course we need these bacteria too thats why a tank is always in flux. There is only so much room and we hope to cultivate a type of bacteria to suit our needs. Thats why some people cycle their tanks with ammonia, it is to try to get those ammonia eating bacteria to occupy space before benign bacteria take up all the space. Cyanobacteria or red slime found a different strategy. They do not need substrait space like most bacteria, they just grow on top of everything else by sending out streamers and grow tent like structures. They are an example of a type of bacteria that do not help us (as far as I know)
Paul

 

[burning2nd]

ohhhhhhhhhh owwwwwwwwwwwwww

growing on top of stuff----->