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Cycle help


AC Members
I have a 55 gallon tank that I am cycling right now. I have used Seachem Stability for the past 7 day and added 9 giant danios and a very small BN Pleco the day that I started using the Stability. I have had water in the tank since the beginning of March. Right now, according to to API master test kit;

pH- around 7.5
Nitrite and Nitrate- 0
Ammonia- 1

My fish all seem fine. Do I just continue to wait for my ammonia and nitrite to rise and lower? Then wait for them to get to 0 and the nitrate to begin to rise? Is that when the tank is cycled? I have also yet to do a water change. Wasn’t sure if I should wait or not?

Any comments or suggestions would be appreciated thanks!


AC Members
ANY ammonia is harmful to your fish. Some are better able to "handle it" than others...but anything over 0.25ppm & you need to do large daily water changes. I know it's a PITA in a larger tank to change water & test but that's what you need to be doing right now.


...and over the edge.
Staff member
Fishy cycle means consistent and regular WCs. Even if your kit read zero, it is still there to some degree. The water change will not slow the cycle.
This will be a long and somewhat detailed post. I tried to keep it as easy to understand as I could. Most of the below is extracted from the second of a two part set of articles I wrote entitled: Rescuing A Fish In Cycle Gone Wild - Part Il

It is not possible to know if your 1 ppm of ammonia is harmful to the fish or not without knowing both the pH and the water temperature. This is because, once in water, ammonia exists in two forms, NH3 is the toxic form and the one we know as smelling awful. However, most of the ammonia will turn to NH4, ammonium. This is nowhere near as bad, especially over the short term. Some say NH3 is 100 times as toxic as NH4.

Unless one is using a test kit that specifically reads NH3 only, what most hobby kits are reading in Total Ammonia (TA) which is the total of NH3 + NH4. The red line for NH3 is at .05 ppm. For most fish we keep in our tanks, NH3 under .05 ppm is safe for some amount of time, i.e. weeks. Here is an example of the above in action. lets assume we have two tanks identical in every way except tank 1 has a pH of 7,0 and the temperature is76F. Tank 2 has a pH of 8.0 and the water temperature is 82F. Both these tanks show a TA level of 1 ppm.

Using an ammonia calculator like the one here https://www.hamzasreef.com/Contents/Calculators/FreeAmmonia.php one can calculate how much of the ammonia in one's water is in each form. Note, NH3 is often referred to as Free Ammonia. This calc allows for a salinity number to be entered so it will take into account fresh, brackish or salt water tanks. For FW, enter 0 for salinity.

Ammonium nitrite and nitrate levels can be measured in two ways. One is only to measure the nitrogen, 1 ppm of Ammonia, 1 ppm of nitrate and 1 ppm of nitrate are all equal. The other way to measure these things is to measure the total ions. This means measuring all the parts of NH3/NH4, NO2 and NO3. H= hydrogen, O = oxygen. So measuiring using the total ion method counts the H and O as Well as the N (nitrogen). Why this matters is that most test kits use the Total Ion scale while science uses the Ntrogen Scale. Normally when the nitrogen scale is used it will change how NH3 is written to NH3-N. That- N indictes the Nitrogen scale is being used. For the ammonia calculator in the link you should normally select NH (NH3 + NH4) for the Total Ammonia Type, Filling in the pH and temperature here are the results:
Tank 1- NH3 = 0.0055 ppm
Tank2- NH3 = .06720 ppm

Tank 1 is safe for fish for a while and no water change should be done based on the numbers, Tank 2 is over the .05 ppm red line and one needs to do a water change. The one caveat is that, while a reading of NH3 under .05 ppm should be safe, this may not be the case. The way one will know is that the fish are behaving abnormally.


Fish will not behave as they normally do. Signs of ammonia poisoning can include sluggish behavior, panting, and gill discoloration (gill burn). Fish may hang just below the water surface or they may hide or stop eating. When you know you have ammonia in the tank during cycling and you notice such behavioral changes, the best course of action, regardless of test results, it to do an immediate water change of 50% or more.

The next thing to understand is that Stability does nothing to establish the bacteria which will be there over the long term. The nitrifying bacteria and ammonia oxidizing Archaea in tanks do not form spores, they reproduce by dividing. When times are hard, they can go into a state of dormancy for some time to survive. They also will become more mobile so some can seek better condition. What is in Stability are spores. They are not the bacteria which will be in your tank once the cycle is established. The actual bacteria in tanks were identified in a series of papers in 1996. 1998 and 2001. I have read all 3. Patents make it impossible to have the "right" nitrite oxidizing bacteria in most cycle starter products. Companies know this, even SeaChem. Have a read here (it was written so long ago that they have the wrong nitrite bacteria listed, the correct one is Nitrospira, not Nitrobacter. http://www.seachem.com/Library/SeaGrams/Biofiltration.pdf

If you want to use a product that is ideal for cycling, then Dr. Tim's One and Only Nitrifying Bacteria or Tetra's Safe Start should be used. The patent involved is shared by the two organizations that make/offer these two products. It is important to understand that the nitrifying bacteria that colonize tanks long term can be killed by letting them freeze or be subjected to extended periods of time over about 104F. So, if you buy either product you need to know they have not been killed due to poor handling. When they are, they are useless. I use Dr. Tim's when I need to restart my biofarm, which I did this past week to have cycled filters for the NEC weekend in April.


Global Moderator
Staff member
Just to add to all the great advice above, when I've done a fish-in cycle in the past, I make it a silent cycle. Meaning, I never want to see ammonia or nitrite. I just do daily water changes until you eventually see nitrates. At which point you gear your water change volume and frequency accordingly. Even with that, I never do less than a 50% weekly.
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AC Members
Thanks for all the info! Should I clean the gravel during these water changes while I’m waiting for the tank to cycle?


...and over the edge.
Staff member