Fishless Cylce: Nitrites won't go down!!

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MadCapLaughs

Aquarium Advice Newbie
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Sep 2, 2020
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I have a ~10 gallon tank that I've been trying to cycle for 21 days now. I started by dosing Dr. Tim's ammonium-chloride to around 2ppm ammonia. About 6 days in I started to test and get readings for nitrites.
Within those 21 days, ammonia has dropped to 0 (I've redosed to 2ppm on the 26th, and ammonia still reads 0), and I have readings for nitrates (Using the API Freshwater Master Test Kit). However, for 2 weeks now, nitrites have remained at a constant 2-5ppm (reads a true purple. My eyesight isn't the best so not sure if it reads 2 or 5ppm nitrites), despite having done 3 PWCs. :(
Temperature sits at around 68F (20C), so perhaps the cooler water is slowing down the cycle? I really don't know.
This is my first time cycling a tank and I'm really at a loss as to what to do. Should I just keep waiting? Another WC? Any advice is more than welcomed!!
 
The cooler water will indeed slow bacteria growth, think about your ham sandwich on the counter vs in the fridge. Sorta the same theory. Takes about 6-8 weeks to fully cycle a tank, so be patient and keep doing what your doing. Your almost there!
 
You are right where i would expect to be after 3 weeks of fishless cycle. Typical fishless cycle is 4 to 6 weeks, and you look to be about 50% through.

How long does it take for 2ppm ammonia to drop to 0ppm?

Getting the nitrites to start dropping normally takes longer than ammonia, and every 1ppm ammonia you dose turns to 2.7ppm nitrite so you also have to cycle out higher concentrations.

You are right about the temperature. 28c is the optimum temperature for growing beneficial bacteria.

Do water changes to keep the nitrite within readable range.

You are right on track, keep on doing what you are, upping the temperature will help a little. You havent mentioned pH. Low pH will slow things down as well.
 
Thank you for the response!!
I re-dosed 2ppm ammonia on the 26th as the ammonia reading at the time was 0ppm. Within 24hr the ammonia readings were 1ppm and within 48 hours the ammonia readings were 0. I'm planning to re-dose again once the nitrites reach 0ppm as well (obv. to ensure the tank is fully cycled haha).
I was previously given the advice to do a WC once the ammonia readings are 0 and re-dose, though not sure the legitimacy of said advice.
pH is 7. My bad for forgetting to include that.
Would doing more frequent WCs be at all beneficial to lower the nitrites present, or would you just recommend letting it cycle out naturally?
I really appreciate your help :)
 
If, when your ammonia gets down to 0ppm your nitrite is too high to read on a test i would do a water change to get it readable.

As mentioned, 1ppm ammonia converts to 2.7ppm nitrite and 3.6ppm nitrate, so your nitrite can quickly go above readable levels if it isnt being cycled out. Some people say that too high a nitrite can stall a cycle, but i do a water change as i like things to stay within readable ranges and make tracking your cycle easier.

Keep up what you are doing. When your tank can cycle out 2ppm ammomia to 0ppm ammonia and nitrite in 24 hours your tank is cycled. If you are planning on starting with a light stocking you can reduce to dosing 1ppm ammonia and cycle that out in 24 hours. In reality a normally stocked tank will never have to deal with producing 2ppm ammonia in 24 hours.
 
If, when your ammonia gets down to 0ppm your nitrite is too high to read on a test i would do a water change to get it readable.

As mentioned, 1ppm ammonia converts to 2.7ppm nitrite and 3.6ppm nitrate, so your nitrite can quickly go above readable levels if it isnt being cycled out. Some people say that too high a nitrite can stall a cycle, but i do a water change as i like things to stay within readable ranges and make tracking your cycle easier.

Keep up what you are doing. When your tank can cycle out 2ppm ammomia to 0ppm ammonia and nitrite in 24 hours your tank is cycled. If you are planning on starting with a light stocking you can reduce to dosing 1ppm ammonia and cycle that out in 24 hours. In reality a normally stocked tank will never have to deal with producing 2ppm ammonia in 24 hours.
Great info for all of us! Things in there I didn't know either. Very helpful
 
If, when your ammonia gets down to 0ppm your nitrite is too high to read on a test i would do a water change to get it readable.

As mentioned, 1ppm ammonia converts to 2.7ppm nitrite and 3.6ppm nitrate, so your nitrite can quickly go above readable levels if it isnt being cycled out. Some people say that too high a nitrite can stall a cycle, but i do a water change as i like things to stay within readable ranges and make tracking your cycle easier.

Keep up what you are doing. When your tank can cycle out 2ppm ammomia to 0ppm ammonia and nitrite in 24 hours your tank is cycled. If you are planning on starting with a light stocking you can reduce to dosing 1ppm ammonia and cycle that out in 24 hours. In reality a normally stocked tank will never have to deal with producing 2ppm ammonia in 24 hours.
Thank you so much! This is all extremely helpful advice. I'll continue to do water changes as necessary and will continue waiting. I appreciate your advice sooo much.
 
Thank you so much! This is all extremely helpful advice. I'll continue to do water changes as necessary and will continue waiting. I appreciate your advice sooo much.
Every time i get a thankyou it makes my time worthwhile.

Fish keeping can be a bit of a rabbit hole, especially when things aren't going as expected. Its a natural process and wont always follow rules, so look at everyone's opinions and you will have to find your own route.

Having said that, i think you are right on track. I wish my last fishless cycle went as well as yours is going. Hope it all goes good for you, and I expect to see some pics of fish when you can post some. Ask if things don't progress, if i can't help, or if my help isn't useful, then someone else will give you the benefit of their experience. While advice may differ, it all worked for them in their own personal circumstances.
 
Every time i get a thankyou it makes my time worthwhile.

Fish keeping can be a bit of a rabbit hole, especially when things aren't going as expected. Its a natural process and wont always follow rules, so look at everyone's opinions and you will have to find your own route.

Having said that, i think you are right on track. I wish my last fishless cycle went as well as yours is going. Hope it all goes good for you, and I expect to see some pics of fish when you can post some. Ask if things don't progress, if i can't help, or if my help isn't useful, then someone else will give you the benefit of their experience. While advice may differ, it all worked for them in their own personal circumstances.
Well said! Every aquarium and every fish is different, and we never stop learning
 
The bacteria that convert ammonia to nitrite and the one that converts nitrite to nitrate are different. They are called nitrosomonas and nitrobacter respectively. The first one colonizes more easily and more quickly than the other. Which is why you will see within a few days that your ammonia drops to zero but it takes an inordinate amount of time for the nitrites to drop.

It is possible that when the level of nitrite is too high it may interfere with the establishment of nitrobacter. If the color looks deep purple, there’s no way to know whether it is 5ppm or 50ppm or 100ppm for that matter. So best to keep up with the water changes and keep the nitrite readings to within a readable range in the test kit.

You can turn up the temperature to 85F. And this will promote the bacteria establishment. Once cycled, you can gradually bring it back down to the range that is comfortable for the fish you decide to keep before you add the fish.

Good luck! Patience is key—you are more than halfway there; good job. And you will definitely get there. Do send an update when your tank is cycled. It is a great feeling when you add fish to your new tank and don’t kill any!
 
Hey everyone! First off, I would like to thank those who came and offered me sound advice when I had no clue what to do.
Good news! My boyfriend had some old filtered media from his tank that he ended up giving to me to help finish out my cycle. My tank is official cycled (as of last week, my bad for a late update), and is ready to be stocked. :)
Thank you all so much for your help!
I think I'm posting this as a reply, so forgive me. I'm not very internet-savvy :brows:
 
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