If a bio-filter was over-loaded, how long would it take to show up on a simple ammonia / Nitrite test? In other words, I have a fairly new tank with a small bio-load. I added some new fish about a week ago and have not seen any change/spike in ammonia or nitrite. If there was going to be an impact on the bio-filter, would I have seen it by now, after 1 week? or could the spike still be ahead? I thought that if I didn't see anything within about 3-4 days, it was safe - but not entirely sure. thanks.
Over-loading a bio filter - how long does it take?
- Thread starter Erik333
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I think you are asking about what is the capacity of the bacteria colonies to deal with increases of waste production. Each individual bacteria's processing amount is very small, but cumulatively there is a maximum amount that can be dealt with and a minimum sustaining amount.
When you are first starting out you may only have 100 bacteria and just for example lets say those 100 can deal with 100 units of waste maximum, and will not decline in number if they get at least 25 units of waste per that 100 bacteria. More than 25 means growth in number can begin and less means die off. Max intake of 1 unit of waste per bacteria just means max growth possible. For our example lets say growth at max is that they double every day. The numbers differ from this and reality is a little more complex than this, but we'll use this to explain.
Once you have your basic stock, lets say your initial stocking load generates 100,000 units of waste, and you start with 100 bacteria. So start 100, day two 200, day three 400, day four 800, day five 1600 and this continues until at some point part way through a day you will have exactly 100,000 bacteria. Finally after this point waste levels start declining, but tests will still show some. One day afterwards you now have 200,000 bacteria, and tested waste levels drop to zero shortly after this. But since 100,000 units of waste will support 400,000 bacteria the numbers still climb but more slowly since they don't have max intake.
What this means is your biofilter has the potential to have a surplus capacity over and above the current production levels of waste. Now in reality there are specific conditions that determine whether you have a large surplus capacity or hardly any at all. So it is wise to pay attention any time you add fish, but it is quite possible that your biofilter had enough surplus capacity to deal with the increase.
It is also possible to damage your bacteria colony that make your biofilter enough to destroy your surplus capacity and have readable ammonia or nitrite levels at any time, which is why we take some precautions with how we treat our filters, and don't recommend the usual cleaning style done to fish bowls which is to take everything out and scrub it down.
When you are first starting out you may only have 100 bacteria and just for example lets say those 100 can deal with 100 units of waste maximum, and will not decline in number if they get at least 25 units of waste per that 100 bacteria. More than 25 means growth in number can begin and less means die off. Max intake of 1 unit of waste per bacteria just means max growth possible. For our example lets say growth at max is that they double every day. The numbers differ from this and reality is a little more complex than this, but we'll use this to explain.
Once you have your basic stock, lets say your initial stocking load generates 100,000 units of waste, and you start with 100 bacteria. So start 100, day two 200, day three 400, day four 800, day five 1600 and this continues until at some point part way through a day you will have exactly 100,000 bacteria. Finally after this point waste levels start declining, but tests will still show some. One day afterwards you now have 200,000 bacteria, and tested waste levels drop to zero shortly after this. But since 100,000 units of waste will support 400,000 bacteria the numbers still climb but more slowly since they don't have max intake.
What this means is your biofilter has the potential to have a surplus capacity over and above the current production levels of waste. Now in reality there are specific conditions that determine whether you have a large surplus capacity or hardly any at all. So it is wise to pay attention any time you add fish, but it is quite possible that your biofilter had enough surplus capacity to deal with the increase.
It is also possible to damage your bacteria colony that make your biofilter enough to destroy your surplus capacity and have readable ammonia or nitrite levels at any time, which is why we take some precautions with how we treat our filters, and don't recommend the usual cleaning style done to fish bowls which is to take everything out and scrub it down.
Yes SnakeIce, that is what I am asking. So would it be your option that since adding fish (last Sunday), had the waste been too great for the bacteria to handle, that a spike in NH3 or NO2 would have been observed within a week's time (or sooner)? I have more fish to add (in quarantine currently) so just wanted to make sure I'm in a safe place before I do.
Great explanation given to you.. but a side note....uneaten food that slowly decomposes is different than waste generated from a digestive system as defined by time.....things could be well for a while then as the decomposing accelerates problems can spike rapidly. Monitor and WC as necessary. And, as always, specific type of fish and stocking levels/tank size should always be included in your questions. Some fish have higher speed systems that don't process food well..often called "dirty" fish as opposed to others that don't.
A fish with an empty stomach is only a minimal additional waste producer in a system that is already established, and this is particularly true with small fish. More often a spike comes from the aquarium keeper's additions via increased food than from the fish themselves. It can still happen from the fish themselves if stock is added to fast, but it sounds like your system is currently handling the (increasing) load.
The other potential source of a spike is from decay, of uneaten food or anything that has died.
The other potential source of a spike is from decay, of uneaten food or anything that has died.
Ok, I didn't know the answer to your question on timing. Per this article: http://www.americanaquariumproducts.com/nitrogen_cycle.html , the bacteria of our interest's doubling rate is between 15-24 hours, so I would think that given an established biofilter any spike would be in the short term, unless the waste production itself is spiking (usually due to decay). Sufficiently small baseline increases would be covered within that doubling time.
One caution is that the growth of the biofilter uses up Kh hardness, which once used up makes your ph less stable. So if your water does not have a high kh to begin with you may need to proceed with bio load increases only as fast as you can replace the kh via water changes.
So tested levels of ammonia would spike if at all in the short term (hours to a day) given baseline waste production increases. Nitrite levels would follow on a slight delay since it is a product of the above. The ultimate test for whether your tank is ready to deal with the newest additions would be whether your kh is sufficiently stable. If kh is still dropping to much between water changes it would not be wise to put more demand on that biofilter "nutrient". Of course you could just do more frequent water changes and add the new fish since your ammonia and nitrite tests come out good.
One caution is that the growth of the biofilter uses up Kh hardness, which once used up makes your ph less stable. So if your water does not have a high kh to begin with you may need to proceed with bio load increases only as fast as you can replace the kh via water changes.
So tested levels of ammonia would spike if at all in the short term (hours to a day) given baseline waste production increases. Nitrite levels would follow on a slight delay since it is a product of the above. The ultimate test for whether your tank is ready to deal with the newest additions would be whether your kh is sufficiently stable. If kh is still dropping to much between water changes it would not be wise to put more demand on that biofilter "nutrient". Of course you could just do more frequent water changes and add the new fish since your ammonia and nitrite tests come out good.
Thanks for the input. As of this afternoon, ammonia and NO2 remain undetected, 10 days after wave of fish added.. kH is very high here. Feeding has been light, 1x per day max.
Good work!
The main thing is, you're keeping an eye on your water parameters and doing your weekly water changes. Simple stuff like having filtration with large amounts of bio media in it, helps when you increase the stocking level.
