Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
The actual species of bacteria that handle the ammonia and nitrite in aquariums thrive under certain conditions, live a long time in the tank, and do not need to be added with every water change. It is a good idea to add them if something compromises the population, but in the day-to-day running of the tank it is a waste of money to keep adding something that is already present and doing fine. The trace of ammonia suggests that there is a problem, but perhaps adding more assorted species of bacteria is not the answer.
Here are some optimum conditions for the nitrifying bacteria that have been properly identified as the major nitrogen cycle species:
These bacteria use the carbon from carbonates (not from organic matter). If the KH is too low they can use it up, and this allows the pH to drop, perhaps too low. I would use baking soda or potassium bicarbonate to keep the KH at 3 German degrees of hardness or higher. 3dKH is fine for the fish you list.
These bacteria seem to do better when the pH is over 6.5. I do not know if this is because of the carbonates, or if there really is a concern with the pH.
I do not know if these bacteria use the minerals that we measure as GH, but I would simply make sure the GH stays at or above 3 degrees. 3 dGH is fine for the fish you list. I know the fish and plants use these minerals.
No medicines. When they are well established, these bacteria are fairly well protected in their biofilm from low doses of antibiotics, but when these bacteria multiply, and grow on new surfaces they are not yet in a developed biofilm. If I remember correctly Gram positive antibiotics are the worst. Antibiotics should not be in the tank when you are trying to grow more bacteria. Many antibiotics have minimal effect on established bacteria, so that is why the label says they do not harm the bio filter.
High oxygen. These bacteria might actually use more oxygen than the fish!
If you want to add more bacteria read the label and add products that include Nitrospira species of bacteria. But do not bother adding them while you are medicating the tank.
In the current situation, adding a bacterial additive and an antibiotic is not going to help anything. The antibiotic will be latching onto all sorts of things, including the debris in the tank, and the bacteria that you just added. By the time it gets around to the disease organisms there will probably not be enough antibiotic to really do the job. It will be busy killing the bacterial additive.
Here is how I would handle this situation:
Larger water changes, if you can keep the GH and KH similar but just a bit higher, than the tank. You can do daily water changes and raise the GH and KH a little each time.
Do as close to vacuuming the substrate as you can. Planted tank, and a plant specific substrate can make this hard, but do what you can. The more debris that is removed from the tank the better.
Gradually raise the GH and KH to a minimum of 3 German degrees of hardness. Then keep them there.
Clean the filter. Rinse the media in water removed for a water change. The biowheels have a pretty good % of the nitrifying bacteria, but while this emergency is going on I would keep the other media, not throw away any beneficial bacteria.
Feed as much plant based foods as the fish are willing to eat. Fish that will eat aquarium plants will usually also eat fresh and lightly cooked vegetables. This will do 2 things. Plant based foods have much less protein than meat based foods, and protein is the biggest source of nitrogen (ammonia, nitrite, nitrate) in the tank. Also, if the fish are nibbling the plants they might need more plants in their diet. By feeding them salad they will probably leave the plants alone.
Improve the conditions for the plants in the tank. Better light, adding carbon, adding other fertilizers (not nitrogen) can help the plants do better so they grow faster and use up more nitrogen.
I would double the filtration. I run the related, older filter, the 350, on a 40 gallon tank. On my 125 I have a sump that moves about 300 gallons per hour, and a canister that moves about 400 gph (per manufacturer- I have my doubts!) and I also run a Koralia power head that moves another 1000+ gph, though not through any filter media.
Finish out the schedule for the antibiotic you have started. While this is going on do as many water changes as you can.
When you are done with the antibiotic do a couple of much larger water changes and add activated carbon to the filter. I do not know if Purigen will remove medications. If it will, go ahead and use it.
Then test the ammonia and nitrite. If you think the tank would benefit from more bacteria then get a product that specifies Nitrospira. There are other species in such a product, too.