During a Cycle How Much Ammonia is TOO Much?

NJBillyV · Aug 7, 2020

Hello Folks,

I'm starting to cycle a new 10g. QT tank with Dr. Tim's One and Only, unfortunately I believe I added too much Ammonium Chloride.

So, I added Dr. Tim's with filter and power head pumps shut off, waited a couple hours, started them back up, waited another couple of hours, then added the Ammonium Chloride.

I've read that the ideal concentration at the beginning of a cycle is .4 ppm, I was shooting for .3 ppm just to be safe, BUT, I must have lost count or something and it ended up being a little over .5 ppm. I let it run overnight then, realizing my mistake, I did a big water change and it was reading .5 ppm exactly. That was 4 days ago and I've seen no signs of cycling, Ammonia still the same, Nitrite and Nitrate still zero.

Did I kill all my good bacteria? Or am I overreacting and just wait?

Brew12 · Aug 7, 2020

NJBillyV said:
Hello Folks,

I'm starting to cycle a new 10g. QT tank with Dr. Tim's One and Only, unfortunately I believe I added too much Ammonium Chloride.

So, I added Dr. Tim's with filter and power head pumps shut off, waited a couple hours, started them back up, waited another couple of hours, then added the Ammonium Chloride.

I've read that the ideal concentration at the beginning of a cycle is .4 ppm, I was shooting for .3 ppm just to be safe, BUT, I must have lost count or something and it ended up being a little over .5 ppm. I let it run overnight then, realizing my mistake, I did a big water change and it was reading .5 ppm exactly. That was 4 days ago and I've seen no signs of cycling, Ammonia still the same, Nitrite and Nitrate still zero.

Did I kill all my good bacteria? Or am I overreacting and just wait?

Dr Tim recommends dosing up to 2ppm so no, you didn't do anything wrong. All the research I have seen suggests that anything below 10ppm ammonia won't harm the bacteria, but slightly different strains of bacteria may prefer the higher ammonia concentrations so you may be encouraging growth of strains that are less effective once the tank matures. Doesn't do any harm though, just slows things down.