Lets put this to rest: Do large water changes have a negative effect on Nitrifying Bacteria / BB

[philipraposo1982]

Hi Everyone,

Claims have been made that performing large water changes have a negative effect (killing / removing) a substantial amount of Nitrifying bacteria which can cause an aquarium to go through a mini cycle or a full blown cycle.

I am hoping that as a community we can prove or disprove this. Feel free to post your opinions and experiences as it will further the discussion.

I will be posting scientific studies and I hope others do the same to help build a backbone to the discussion.

Some general information about nitrifying bacteria
http://www.bioconlabs.com/nitribactfacts.html

 

[philipraposo1982]

While this is not a scientific pape the small blurb on tank maintenance is of importance in this discussion. For those wondering who Dr. Strom is look here: https://eoas.rutgers.edu/about/faculty-directory/peter-strom/

The artical can be found here: http://www.tfhmagazine.com/aquarium-basics/columns/nitrifying-bacteria.htm

Interesting statistic:
For every gram of ammonia oxidised into nitrate 4.8 grams of oxygen is used, 7.14 grams of calcium carbonate is used (now you know why pH crash can occur in tanks with to little buffering capacity).

Why is why frequent water changes are important to prevent ph from crashing which will kill the bacteria if its begins to drop below 6.

 

[koltsixx]

I understand the nitrogen cycle and beneficial bacteria's role in it. I how ever can not personally assert negatively or positively about the possible effect of large water changes on Beneficial Bacteria I can only go by what I know and what I would consider logical deduction based on it. In other words I can give my opinion.

Tap water has numerous chemicals added to it to kill bacteria and also has contaminants that may also be harmful. Here is a list of just a few of the chemicals routinely added to our water supply:

• Liquified chlorine
• Fluorosilicic acid
• Aluminium sulphate
• Calcium hydroxide
• Sodium silicofluoride

And here are some commonly found contaminants.

• Chlorine
• Fluorine compounds
• Trihalomethanes (THMs)
• Salts of:
  • arsenic
  • radium
  • aluminium
  • copper
  • lead
  • mercury
  • cadmium
  • barium
• Hormones
• Nitrates
• Pesticides

Most water conditioners tend to focus on specifically chlorine, chloramine, and ammonia. And they detoxify nitrite and nitrate and help protect and stimulate growth of the slime coat.

That being said I believe that since there is no mention of how fast the reaction of the conditioners will take effect and that they don't seem to cover all the chemicals and contaminant I believe large water changes may under certain circumstances negatively effect Beneficial Bacteria. Do I think in general large water changes are a bad practice? Meh, hard to say. I wouldn't say it's a bad practice but I would be wary if I did them. And would prefer to age my water if I did do large water changes. I know when you're are first setting up an aquarium you can disturb and even slow the initial cycle with too may water changes and I imagine similarly under certain circumstances the same could happen to established tanks.

 

[koltsixx]

I think it maybe of importance to clarify what a large water change is as many may perceive it differently. I believe you asserted in the other thread that 90% daily water changes wouldn't effect the tank in any negative way. So I'm basing my answer on such a routine. For instance in your tank that would mean everyday you'd only leave 7.5 gallons of original tank water between your filters and actual tank.

 

[Drstrangelove]

Claims have been made that performing large water changes have a negative effect (killing / removing) a substantial amount of Nitrifying bacteria which can cause an aquarium to go through a mini cycle or a full blown cycle.

I've never heard this.

Regardless, I've never believed it. How could removing 90% of the part of the tank (water) that has less than 5% of the bacteria, cause a mini cycle or a full blown cycle in a previously fully cycled tank?

Of course... if the water has chlorine or chloramine, that's different. If the BB is exposed to the atmosphere long enough to dry out (and thus die), that's different. If the tank is not cycled and you are removing food the BB needs, that's different. Otherwise, I don't know where this is a controversy that needs to be studied and resolved.

Maybe rivers, where 90% of the water is changed every 30 minutes (or less), are missing BB as well?

 

[koltsixx]

I've never heard this. Regardless, I've never believed it. How could removing 90% of the part of the tank (water) that has less than 5% of the bacteria, cause a mini cycle or a full blown cycle?

I assumed said tank water would flow through the filter where the bacteria are established and would be similar to rinsing your filter media in such water. Again unless the effect of the conditioners is instantaneous that is.

 

[philipraposo1982]

"That being said I believe that since there is no mention of how fast the reaction of the conditioners will take effect"

Seachem Prime is the only conditioner I used and it binds instantly.

"would prefer to age my water if I did do large water changes"

What is accomplished by aging water in terms of removing chemical compounds that have a negative effect on the bacteria?

I understand that you can stabilize the PH as well as allow for off-gassing but I am unaware how the harmful compounds are removed of dealt with.

"I know when you're are first setting up an aquarium you can disturb and even slow the initial cycle with too may water changes and I imagine similarly under certain circumstances the same could happen to established tanks."

What exactly are you disturbing by doing a water change? As the bacteria develops it creates a bio-film that keeps the bacteria rooted or fixed in the aquarium. They cannot be removed from the aquarium by changing the water.

If you referring to removing its "food" then I can agree that this may happen but doing a 50-75% water change is not going to remove all the organic salts required for the nitrifying bacteria to grow.

 

[philipraposo1982]

I assumed said tank water would flow through the filter where the bacteria are established and would be similar to rinsing your filter media in such water. Again unless the effect of the conditioners is instantaneous that is.

You would not have your filters running if your doing a 90% water change. Also Prime work instantly. Not to mention that you cannot remove the bacteria by remove the water. Its anchored to the bio media, substrate, glass surface, ornaments and literally all surfaces with bio-film.

I think we need to clarify that when I said performing a larger water change I am making the assumption that the water itself is treated in a way which the bacteria is not going to be killed by chemicals in the water. Otherwise even a small 25% of untreated water would have negative effects on the life in that aquarium.

 

[Drstrangelove]

I assumed said tank water would flow through the filter where the bacteria are established and would be similar to rinsing your filter media in such water. Again unless the effect of the conditioners is instantaneous that is.

Water conditioners like dechlorinators are instantaneous anywhere within the normally largest size of any tank. Obviously, a 50,000 gallon tank would not be quite as fast, but that is an extreme.

 

[koltsixx]

"That being said I believe that since there is no mention of how fast the reaction of the conditioners will take effect"

Seachem Prime is the only conditioner I used and it binds instantly.

While the binding action maybe instant doesn't it have to spread through the water so the action may take effect? I imagine that would take some time, maybe not much but as I said I'm just giving my opinion.

"would prefer to age my water if I did do large water changes"

What is accomplished by aging water in terms of removing chemical compounds that have a negative effect on the bacteria?

I understand that you can stabilize the PH as well as allow for off-gassing but I am unaware how the harmful compounds are removed of dealt with.

I didn't say it would I merely said I'd be wary in either instance and would prefer to age my water if I did. I believe it was I who mentioned out gassing in my other posts I guess I should have hear as well to be clear. My apologies.

"I know when you're are first setting up an aquarium you can disturb and even slow the initial cycle with too may water changes and I imagine similarly under certain circumstances the same could happen to established tanks."

What exactly are you disturbing by doing a water change? As the bacteria develops it creates a bio-film that keeps the bacteria rooted or fixed in the aquarium. They cannot be removed from the aquarium by changing the water.

If you referring to removing its "food" then I can agree that this may happen but doing a 50-75% water change is not going to remove all the organic salts required for the nitrifying bacteria to grow.

Again I mentioned the chemicals and contaminants that could kill the BB. I never used the word removed and if I did I misspoke and apologize. I myself do 35%-50% water changes so under those parameters I feel any effect would be minimal. How ever at 90% and daily I imagined enough of said chemicals may find their way into the filter before the conditioner could take effect to possibly kill off some of the beneficial bacteria in them.