Stubborn ammonia level in cycling

[think2100]

I’m going on three weeks into a no fish cycle starting with Microbacter xlm and ammonium chloride. I thought the ammonia dropped to 0 after a few days, but in retrospect, I may have done something wrong on that first test. I’m using Hannah test kits. Nitrites remained at pretty low, but persistent, levels and nitrates never really took off. Then after about 10 days, ammonia showed up at 1.05 ppm. Nitrites and nitrates remained about the same as before. Things seemed to be stuck there so I started dosing Microbacter7 for a few days, but that just seemed to nudge the ammonia down a bit. Since then I’ve done two 30% water changes and halved the ammonia twice down to .27 ppm, dosing MB7 after each water change. I’m not sure why everything seems to be stuck. Never saw the classic drop in ammonia with sharp rise in nitrite or decline in nitrite with sharp rise in nitrate. I have about 2 inches of oolitic sand and dry Caribsea rock in the tank.

 

[Dan_P]

I’m going on three weeks into a no fish cycle starting with Microbacter xlm and ammonium chloride. I thought the ammonia dropped to 0 after a few days, but in retrospect, I may have done something wrong on that first test. I’m using Hannah test kits. Nitrites remained at pretty low, but persistent, levels and nitrates never really took off. Then after about 10 days, ammonia showed up at 1.05 ppm. Nitrites and nitrates remained about the same as before. Things seemed to be stuck there so I started dosing Microbacter7 for a few days, but that just seemed to nudge the ammonia down a bit. Since then I’ve done two 30% water changes and halved the ammonia twice down to .27 ppm, dosing MB7 after each water change. I’m not sure why everything seems to be stuck. Never saw the classic drop in ammonia with sharp rise in nitrite or decline in nitrite with sharp rise in nitrate. I have about 2 inches of oolitic sand and dry Caribsea rock in the tank.

I assume you are using Start XLM. Could just be a slow product like Dr. Tim’s or a dud bottle. Not sure Microbacter 7 will do much for you.

As for the ammonia level, the Hannah Checker baseline can vary depending on the reagent lot. A reading of 0.27 could actually be 0 ppm total ammonia.

My guess is that you had sluggish bacteria and your initial ammonia was low.

 

[Ryanliyikun]

This actually sounds like a stalled cycle, which can happen with dry rock and sand since there’s very little initial bacteria. The fact that ammonia is lingering and you’re not seeing a clear nitrite/nitrate progression means the bacteria population just hasn’t fully established yet. I’d stop doing water changes and stop redosing ammonia for now—just let it sit and keep dosing bacteria consistently. Sometimes these cycles take longer with dry setups, but once it kicks in, you’ll see ammonia drop quickly and nitrates finally rise

 

[Fish Fan]

It's not uncommon for a fish-less cycle with bottled bacteria to take 3 to even 4 weeks, despite what the bottle says

The exception to this seems to be Fritz TurboStart, which works much more quickly than the others.

But to be clear, what are you using for test kits? Did you dose the ammonia and measure it at about 2.0 ppm when the tank was first started? Without knowing how high the ammonia was initially, it's difficult to tell what's going on.

You can't have high nitrites and zero nitrates, without test it error Nitrites will cause an artificial high for nitrate, so something seems wrong with your testing

And other than the concern above about nitrate testing, you can safely ignore testing for nitrite, it's non-toxic, and not an issue in marine aquaria

I hope that helps!

 

[Randy Holmes-Farley Verified Community Expert]

Why did you do the water changes?

FWIW, new salt water can contain some ammonia too.

I agree the cycling is likely just slow. As mentioned, Fritz turbo is much faster and I’d add it if you want to go faster, or just wait it out.

 

[think2100]

Why did you do the water changes?

FWIW, new salt water can contain some ammonia too.

I agree the cycling is likely just slow. As mentioned, Fritz turbo is much faster and I’d add it if you want to go faster, or just wait it out.

I had dosed the original ammonia for a 65 gallon tank, which is what my DT is and then thought that perhaps I had not taken into account enough displacement from rock and sand and had overdosed the ammonia. So I diluted it through water changes.

 

[think2100]

Why did you do the water changes?

FWIW, new salt water can contain some ammonia too.

I agree the cycling is likely just slow. As mentioned, Fritz turbo is much faster and I’d add it if you want to go faster, or just wait it out.

This is a used tank, and although the previous owner cleaned it with citric acid and RO water, perhaps residual organic material is decaying and causing ammonia to hang on.

 

[Randy Holmes-Farley Verified Community Expert]

I doubt there’s any explanation needed other than some cycling bottled bacteria products are quite slow to work.

 

[think2100]

I doubt there’s any explanation needed other than some cycling bottled bacteria products are quite slow to work.

Thanks. Good to know what’s going on.