Stalled Cycle?

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Hey everyone,

I set up a 15-gallon rimless cube on September 29th using dry rock, CaribSea live sand, and Dr. Tim’s One and Only. On October 1st, I added a pair of small clownfish and have been attempting a fish-in cycle since then.

Both clowns have been doing great — healthy, active, and eating well. I feed them daily (around 15–20 pellets), though a few uneaten pellets usually end up in the filtration chamber. (I do have frozen food as well I've fed once or twice)

I’ve been using the API Master Saltwater Test Kit to monitor water chemistry. While I realize it’s not the most precise test kit out there, I expected to at least see some movement in the cycle by now. My readings have been very consistent for the past few weeks (ammonia became present around October 15th). As of today, they are as follows:
  • Ammonia: 0.25 ppm (maybe even slightly less than 0.25 ppm, but it is sometimes hard to read on the API test)
  • Nitrite: 0 ppm
  • Nitrate: 0 ppm
Given that it’s been over three weeks, I would’ve expected to see at least a hint of nitrite by now. It feels like nothing is happening at all.

I also have two pounds of live rock rubble from Tampa Bay Saltwater arriving this Friday, which I'm hoping will introduce some biodiversity and beneficial bacteria into the system. I can temporarily keep it in a separate bucket if needed before adding it to the display.

My question is: does this cycle sound like it’s on track? I know the fish-in approach can be slower and I want to keep ammonia low for their sake, but I’m surprised there’s been no sign of nitrite or nitrate after three weeks.

Any insight or suggestions would be appreciated!
 

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The full cycle process might not be complete for a couple months. You’re on the right track but I would continue or start dosing some sort of beneficial bacteria to help it get along. The live rock will help but you may not see nitrite or nitrates for several more weeks.
 
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The full cycle process might not be complete for a couple months. You’re on the right track but I would continue or start dosing some sort of beneficial bacteria to help it get along. The live rock will help but you may not see nitrite or nitrates for several more weeks.
I'm currently dosing stability by Seachem daily. I could get other bottled bacteria as well
 

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While I don't agree with doing fish-in cycles, using the Dr. Tim's One and Only product a tank usually cycles in about 3 weeks, give or take. I think your tank is cycled.

Something is up with your testing. The API ammonia test kit is well know to always show about 0.25 ppm ammonia when other indicators would suggest that the ammonia level is much lower, like the time the system has been running.

0.25 ppm ammonia is not dangerous to your fish or other live stock at all, corals and macro algae will even uptake ammonia directly from the water column. So I wouldn't stress over this number.

You can safely ignore testing for nitrite entirely, it's not toxic in marine systems like it is in freshwater systems.

You absolutely should have some nitrate by now, likely a lot as nitrite causes high test values for nitrate. So I believe something is wrong with your testing. Try taking a sample to your LFS for testing, or looking into tests from Salifert (for nitrate, don't bother buying a new test kit for ammonia or nitrite, you don't need them).

Good luck!
 

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I'm currently dosing stability by Seachem daily. I could get other bottled bacteria as well
You have all the bacteria you need, just let the system do its thing. Adding too many of these bottled bacteria products sometimes introduces the wrong kind of bacteria that we want long-term, and can cause a bacteria bloom that can result in dangerously low oxygen levels for your fish.

I hope that helps!
 
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You have all the bacteria you need, just let the system do its thing. Adding too many of these bottled bacteria products sometimes introduces the wrong kind of bacteria that we want long-term, and can cause a bacteria bloom that can result in dangerously low oxygen levels for your fish.

I hope that helps!
Thanks for the input! I've been testing like a mad man considering I have actual FISH in the tank lol! It has not occurred to me that something may be wrong with the test -- I definitely will get another set of eyes on it.
 

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Thanks for the input! I've been testing like a mad man considering I have actual FISH in the tank lol! It has not occurred to me that something may be wrong with the test -- I definitely will get another set of eyes on it.
Yes, the API brand tests don't get a lot of love on R2R, I personally don't think they're that bad, but in this case something isn't adding up right 🤪 Many of us like the Hanna Checkers, but they can be a touch speedy. Salifert is one of the go-to brands for cost, reliability, and ease of use 🙂
 
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Yes, the API brand tests don't get a lot of love on R2R, I personally don't think they're that bad, but in this case something isn't adding up right 🤪 Many of us like the Hanna Checkers, but they can be a touch speedy. Salifert is one of the go-to brands for cost, reliability, and ease of use 🙂
As it so happens, the salifert kits can be delivered to my house by 7 AM tomorrow if you can believe it! Might as well do that! Thanks!! I'll update with the new numbers at some point
 
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Yes, the API brand tests don't get a lot of love on R2R, I personally don't think they're that bad, but in this case something isn't adding up right 🤪 Many of us like the Hanna Checkers, but they can be a touch speedy. Salifert is one of the go-to brands for cost, reliability, and ease of use 🙂
So, I just decided to test my nitrates one final time with the API test kit just now...and upon closer look, it appears that nitrates actually *ARE* present. I made sure to follow the instructions extremely carefully this time. I think that is great news!

thumbnail_IMG_6878.jpg
 

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That is good news, though I'd expect to see more for nitrate at this point, especially because any nitrite that may be in the system (and I would suspect you likely have some) would cause a false positive for nitrate in testing. But definitely good news, let us know what you get from the Salifert test when you get it 🙂
 

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