Cycle Troubleshooting – 13 things you need to consider.

It is important to realize that bacteria are living organisms that respond, positively or negatively, to the conditions you put them in. To cycle your tank quickly please review the points below preferably before you set-up the tank.  Also download our step-by-step recipe card to help guide your through the process.


1. Fishless Cycling Takes Longer - For some reason people think fishless cycling only takes a few days. Wrong. Fishless cycling takes longer than cycling with fish. Fishless cycling takes 10 to 14 days because you, the aquarist, are adding a lot of ammonia. Cycling with fish where you add a FEW fish and the bacteria generally takes 4-5 days but this is at a lot lower level of ammonia. There is no wrong way to cycle just have a little patience,

2. Live Sand - if you are going to use live sand chances are high that cycling with take a little longer. Live sand contains organics and bacteria that breakdown those organics into ammonia. This causes two issues - high ammonia which slows the process and a bacteria bloom. Those bacteria take micro-nutrients out of the water which the nitrifiers need when fishless cycling. Follow the set-up guide for the tank and get everything running. After 24 hours measure the ammonia BEFORE adding the ammonium drops. If your water has ammonia then do not add the ammonia drops at this stage. Wait until ammonia disappears before adding more,

3. Bare-Bottom or lack of biomedia – Bare-bottom tanks take longer to cycle because the bacteria need a lot of surface to stick too. Bare-bottom tanks lack surface area. The glass (or plastic) bottom of the aquarium is not a good surface. This is especially true in quarantine systems - there is not enough good surface area for the bacteria. Many types of sponges are not great, either. Plus with lots of water circulation the bacteria are swept into the mechanical filter and when it is cleaned they are tossed-out. One solution, if you really want the look of a bare-bottom tank, is to add a layer of glass beads or marbles to the bottom. Cycle the tank and then slowly start to remove the marbles over a week or two AFTER cycling,

4. Space Age media - Along with #3, people will use an artificial media made from glass, ceramic or some other space age media. While these can work eventually the bacteria don’t seem to colonize them very fast. So just putting a few blocks in an otherwise bare-bottom tank will not work well. Also remember long-term these types of media need to be kept clean so water can freely flow through them,

5. The Water Needs to be Chlorine/Chloramine Free - Most tap water contains chloramines or chlorine to kill bacteria and make the water safe to drink. These chemicals need to be neutralized before adding the One & Only Live Nitrifying Bacteria. Use our First Defense to detoxify your water,

6. High Ammonia - People think they have to feed the bacteria every day or the bacteria will starve. Bacteria are not human; they do not need to eat every day to survive. Because the ammonia-oxidizing bacteria work faster than the nitrite-oxidizing bacteria the ammonia will read zero sooner than the nitrite will read zero. Don’t believe the internet that says the bacteria will starve if there is no ammonia. Follow the recipe directions - 1) do not add ammonia if either ammonia or nitrite is above 5 mg/L-N and 2) only add a maximum of 4 drops per gallon do not continue to add ammonia until you get a reading of 2 ppm or else you risk overdosing the system with ammonia,

7. Overdosing with Ammonia-Removing Chemicals - It makes little sense to add an ammonia-removing chemical to your aquarium water when you are then going to add ammonium chloride drops. So don’t! Just use a ‘simple’ dechlorinating agent like our First Defense to remove any chloramines or chlorine. Some popular brands of ammonia-removers advertise that they do not affect the nitrifying bacteria even at high doses - this is wrong. The overuse of ammonia-removing chemicals will stall the cycle,

8. High Nitrite - Related to #6. Many times the bacteria can quickly handle the overdosing of ammonia and you will get a zero (0) ammonia reading but the nitrite just gets higher and higher. High nitrite is very common when you rush the process or add too much ammonia too quickly. High nitrite inhibits the bacteria and stalls the cycle. If you have super high nitrite do a 33-50% water change without disturbing the substrate. Do not add chemicals to de-toxify the nitrite,

9. No Nitrite - The opposite of #8. The bacteria work so well that there is no nitrite and so you assume the bacteria are dead. If your water is ammonia and nitrite-free follow the recipe card and add another dose of ammonia. The goal of adding One and Only is to add enough bacteria to remove the ammonia and nitrite quickly and in many cases you may not see either while cycling,

10. No Nitrate - The end product of nitrification is nitrate. So logically you should be able to measure nitrate to make sure your aquarium is cycled – this is correct. The issue is that the majority of nitrate tests do not measure low nitrate values very well. Until the nitrate get around 20 mg/L the kits may not register a reading,

11. Low pH/ Soft Water - the nitrifying bacteria do not work fast at low pH values (under 7). They also don’t work fast in RO/DI water or naturally soft water. It may seem to make sense that pure water is the best - it’s pure! But that is not true. The bacteria need water with minerals and they prefer water with a higher pH value.

12. Specialized Tanks - plant tanks, shrimp tanks etc. with specialized soils that leach ammonia or keep the pH low or add lots of tannins to the water all negatively affect the performance of the bacteria. That means cycling will take longer. You either need to be patient or add a lot more nitrifying bacteria to the system,

13. Temperatures During Shipping - Nitrifying bacteria are relatively tough bacteria especially ours because we grow them on a small particle (which is why you need to shake the bottle well before adding them to the tank). They tolerate heat very well and only when exposed to temperatures over 130°F for several days do they suffer. At the other extreme, they do not survive freezing and if the bottle arrives frozen solid chances are the bacteria did not survive. If the temperatures in your area are at either of these extremes purchase the extreme weather package (Item#799P).