Symptoms of a Stalled Fishless Cycle and How to Fix it

mattgirl

Member
You have been going along adding ammonia and it is all gone by the next day. You are seeing both nitrites and nitrates. The nitrites are off the chart because the color in the test tube is a rich purple. They could be 5 or they could be 50

Your nitrates are steadily going up and then one day they drop back down to 5 and stay there. It seems once the amount of nitrates reaches a certain number and the nitrites are off the chart the nitrate test defaults back down to 5. I have only seen this happen when both nitrites and nitrates are off the chart.

Along about this time the ammonia takes longer to go back to zero or stops going down at all.

You have been told not to do water changes during this time and to just allow the cycle to progress so you still have the same water in there as you started with. Maybe you have topped it off, maybe you haven't.

Your cycle is stalled because it is so far out of balance it can't right itself and the water you started with is dead. All of the minerals present in your tap water have been used up.

There is a simple fix for a stalled cycle. Change the water to get both nitrites and nitrates down and replenish the necessary minerals. The bacteria we are growing doesn't live in the water so even a 100% water change will not be removing bacteria. A 100% water change shouldn't be necessary though. Start with 50%. Check your numbers. If they are still off the chart do another 50%. It may take more than 2 50% water changes.

Be sure to temp match and dechlorinate the water you are replacing if you have chlorine/chloramines in your source water. We can't see bacteria but it is a living thing and needs to be handled with care while getting well established in our tanks.

Once you get both nitrites and nitrates down to readable numbers go ahead and add ammonia again. Run your tests the next day. You may very well find that your cycle is done or very close to done. Either way this will get your cycle moving forward again.
 

nikm128

Member
Sticky this Coradee ?
Great post mattgirl it's very well worded and easy to understand. Next time I go sticking my nose in this section of the forum I'll keep this in mind.
 

kallililly1973

Member
Amazing way of explaining the Cycle mattgirl and I was also going to suggest making this a sticky nikm128 I definitely second that suggestion!!! Amazing post!! Bravo!!
 
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mattgirl

Member
I don't normally do this but I am going to bump this back to the top so those that need it can find it easily. I do hope it is alright to do this. If not I won't do it again.
 

Virgo

Member
Agree fully. I think a lot falls into the trap of not doing WC when both nitrites and nitrates are off the chart, and eventually the ammonia readings stalled. I’m one of them. Now doing big water changes of at least 50%. Just did a 50% then 75-80% WC in the other half of the day. Fingers crossed.
 
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mattgirl

Member
Virgo said:
Agree fully. I think a lot falls into the trap of not doing WC when both nitrites and nitrates are off the chart, and eventually the ammonia readings stalled. I’m one of them. Now doing big water changes of at least 50%. Just did a 50% then 75-80% WC in the other half of the day. Fingers crossed.
Hopefully this will get your cycle moving forward again
 

Sorg67

Member
Excellent explanation. Bumpimoto.....
 

tuffcookie

Member
I’ve been cycling for almost 3 weeks which is probably still early. every time I dose ammonia to 4 it drops to around 1-2 next day, still never 0. Nitrites consistently stay at deep purple everyday. Nitrates even with 1 pump nilcog stays around 5. I think I’ll do a water change tonight and see what happens?
 
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mattgirl

Member
tuffcookie said:
I’ve been cycling for almost 3 weeks which is probably still early. every time I dose ammonia to 4 it drops to around 1-2 next day, still never 0. Nitrites consistently stay at deep purple everyday. Nitrates even with 1 pump nilcog stays around 5. I think I’ll do a water change tonight and see what happens?
You can get a better idea as to high your nitrites actually are by doing a dilution test. Put 1ml of tank water and 4mls of your source water in the test tube and run the test on that mixture. If you still get the deep purple you will know that your nitrites are well beyond the highest number on the chart. If you are seeing a lower number you know you can get them down to that number by doing an 80% water change.

You could do the same dilution test for your nitrates. If the test has defaulted back down to 5 you should get a higher number with the dilution test.

I can't imagine your nitrites and nitrates pegging out the chart and nitrates defaulting back down to 5 this early in the cycle but it certainly could happen.
 

tuffcookie

Member
mattgirl said:
You can get a better idea as to high your nitrites actually are by doing a dilution test. Put 1ml of tank water and 4mls of your source water in the test tube and run the test on that mixture. If you still get the deep purple you will know that your nitrites are well beyond the highest number on the chart. If you are seeing a lower number you know you can get them down to that number by doing an 80% water change.

You could do the same dilution test for your nitrates. If the test has defaulted back down to 5 you should get a higher number with the dilution test.

I can't imagine your nitrites and nitrates pegging out the chart and nitrates defaulting back down to 5 this early in the cycle but it certainly could happen.
Ok thank you I’ll do that tonight and see. It’s still super early but I did toss a dirty sponge from my other tank in the filter and some plants. Still a newb so wasn’t too sure how much of an impact that is having, if any at all at this point
 
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mattgirl

Member
tuffcookie said:
Ok thank you I’ll do that tonight and see. It’s still super early but I did toss a dirty sponge from my other tank in the filter and some plants. Still a newb so wasn’t too sure how much of an impact that is having, if any at all at this point
If the other tank is cycled then adding a sponge from it would have jump started this cycle. I often instantly cycle a tank with media from my well stocked cycled tank. The amount of bacteria on the media depends on the bio-load of the tank the media comes from.

The sponge didn't instantly cycle this tank. Had it done so you wouldn't have had a nitrite spike and the ammonia you added would have gone down quickly. It looks like it did add some bacteria though and that is the reason you are as far along in the cycling process as you are now.
 

Virgo

Member
mattgirl said:
You can get a better idea as to high your nitrites actually are by doing a dilution test. Put 1ml of tank water and 4mls of your source water in the test tube and run the test on that mixture. If you still get the deep purple you will know that your nitrites are well beyond the highest number on the chart. If you are seeing a lower number you know you can get them down to that number by doing an 80% water change.

You could do the same dilution test for your nitrates. If the test has defaulted back down to 5 you should get a higher number with the dilution test.

I can't imagine your nitrites and nitrates pegging out the chart and nitrates defaulting back down to 5 this early in the cycle but it certainly could happen.
Looks like this was what happened to my 3.5g tank before.
 

tuffcookie

Member
I did the test tonight, got the same result I’ve been getting for a week now. Also did dilution test

1st pic with 4 tubes is the regular test
2nd pic with 2 tubes is the dilution test

Came out to be the same colors

Sorry pic and lighting quality is horrible. But in real life, nitrites are >5ppm and nitrates are about 5ppm


IMG_0620.JPG

IMG_0622.JPG
 
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mattgirl

Member
tuffcookie said:
I did the test tonight, got the same result I’ve been getting for a week now. Also did dilution test

1st pic with 4 tubes is the regular test
2nd pic with 2 tubes is the dilution test

Came out to be the same colors

Sorry pic and lighting quality is horrible. But in real life, nitrites are >5ppm and nitrates are about 5ppm


IMG_0620.JPG

IMG_0622.JPG
The dilution test is telling us that your nitrites need to come down and that can only be accomplished with water changes. Seeing that deep purple in a dilution of 1 part tank water and 4 parts source water tells us that even an 80% water change won't be enough.

Do you have any idea as to exactly how much ammonia this tank has processed? You said you add enough to get it up to 4ppm and it drops down to 1 or 2. Does it ever go down close to one or do you dose it back up to 4 each time it drops back to 1 or 2?

BTW: What size is this tank? What temp are you keeping the tank at?
 

tuffcookie

Member
mattgirl said:
The dilution test is telling us that your nitrites need to come down and that can only be accomplished with water changes. Seeing that deep purple in a dilution of 1 part tank water and 4 parts source water tells us that even an 80% water change won't be enough.

Do you have any idea as to exactly how much ammonia this tank has processed? You said you add enough to get it up to 4ppm and it drops down to 1 or 2. Does it ever go down close to one or do you dose it back up to 4 each time it drops back to 1 or 2?

BTW: What size is this tank? What temp are you keeping the tank at?
40gallon. I think I messed it up. I had thought I was supposed to dose to 3 to 5 ppm every time I see it fall down below 3. I read somewhere else that I’m supposed to wait for initial dose to get to 0 before redosing. Head desk moment, this is my first time doing fishless cycle

Every time I redosed it went back down to 1 to 2 ppm the next day

I’ve redosed 3 times total since 11/21 or so I’ll have to check my excel document when I get home. It’s hot in Texas, my other tanks stay at ~80 to 82, without any help from heater so I didn’t bother to put a heater on. But I do have 1 I could use.

Lights also off this entire time except for picture time and I think I have black algae too. The struggle is real
 
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mattgirl

Member
tuffcookie said:
40gallon. I think I messed it up. I had thought I was supposed to dose to 3 to 5 ppm every time I see it fall down below 3. I read somewhere else that I’m supposed to wait for initial dose to get to 0 before redosing. Head desk moment, this is my first time doing fishless cycle

Every time I redosed it went back down to 1 to 2 ppm the next day

I’ve redosed 3 times total since 11/21 or so I’ll have to check my excel document when I get home. It’s hot in Texas, my other tanks stay at ~80 to 82, without any help from heater so I didn’t bother to put a heater on. But I do have 1 I could use.

Lights also off this entire time except for picture time and I think I have black algae too. The struggle is real
You really didn't mess up. One of the good things about fishless cycling is things like this won't harm fish

Temp is fine if it stays up that high without a heater. I also noticed from your previous photos that your PH is good so conditions are good for a successful cycle.

Have you run all the tests on your source water? It is always a good idea to have baseline numbers on the water you are using for water changes.

For now the one thing I would recommend you do is get those nitrites down to no more than 2 even if it takes several water changes to accomplish it. Be sure to condition and temp match the water you are putting back in there. Once you do that add enough ammonia to get it up to 2ppm. Don't add any more until it drops down to .25 or less.
 

tuffcookie

Member
mattgirl said:
You really didn't mess up. One of the good things about fishless cycling is things like this won't harm fish

Temp is fine if it stays up that high without a heater. I also noticed from your previous photos that your PH is good so conditions are good for a successful cycle.

Have you run all the tests on your source water? It is always a good idea to have baseline numbers on the water you are using for water changes.

For now the one thing I would recommend you do is get those nitrites down to no more than 2 even if it takes several water changes to accomplish it. Be sure to condition and temp match the water you are putting back in there. Once you do that add enough ammonia to get it up to 2ppm. Don't add any more until it drops down to .25 or less.
I did >80% wc last night, here’s what I’m getting today. The ammonia has dropped significantly but nitrite still off the charts. WC again today? The seachem ammonia indicator was at green 3hrs after WC but yellow this morning.

I also swapped out the canister filter unit last night, not sure if that made any impact. I put all the sponges, etc into the new one but the activated carbon because the bag didn’t fit in the new unit


IMG_0641.JPG


IMG_0643.JPG
 
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mattgirl

Member
Looks like your nitrites were super high since they are still this high after the water change but of course we already knew that. We know that your cycle is moving forward because the ammonia went down. I would just go ahead and add ammonia again and see where you are tomorrow. It is possible the water change will have got things moving forward better and if that is the case these nitrites should start going down on their own within a few days.

If they don't within 3 or 4 days another big water change may need to be done.
 

Virgo

Member
Yes I think you’re good too. At least your ammonia eating guys are working. Mine just got stuck at where it was until I made water changes. Not sure why really.
 

Florin79

Member
I have a 29 gallons tank and this is my second week of cycling. At the beginning I put some bacteria from Fritz zyme ( I think that's the name).
Until now I try to feed my amonia eater bacteria well fed. My nitrites are somewhere around 5 ppm .I do daily water hanges to get the nitrites down to 0 and add amonia after to raise it at 2ppm. Is this the right way? I mean to do daily water changes?
I can't edit my post . My amonia is going from 2 to 0 in less then 24h.
 
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mattgirl

Member
Florin79 said:
I have a 29 gallons tank and this is my second week of cycling. At the beginning I put some bacteria from Fritz zyme ( I think that's the name).
Until now I try to feed my amonia eater bacteria well fed. My nitrites are somewhere around 5 ppm .I do daily water hanges to get the nitrites down to 0 and add amonia after to raise it at 2ppm. Is this the right way? I mean to do daily water changes?
I can't edit my post . My amonia is going from 2 to 0 in less then 24h.
Since this is a fishless cycle the daily water changes are not necessary. As long as the ammonia you add each day continues to go down to 0 within 24 hours your cycle is still moving forward. Right now it is just a waiting game, waiting for enough ammonia and nitrite eating bacteria to grow. When you see 0 ammonia and 0 nitrites within 24 hours of adding ammonia and the nitrates are gradually going up you will know your cycle is done.
 

Florin79

Member
I knew that is not so good to let the nitrates go above 3 ppm. That's the reason of water changes. I have 29 degrees, ph is 7.6 and stabile . Good sings. Should I stop hange the water and leave it as it is? Nitrites will climb sky high.
 
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mattgirl

Member
Florin79 said:
I knew that is not so good to let the nitrates go above 3 ppm. That's the reason of water changes. I have 29 degrees, ph is 7.6 and stabile . Good sings. Should I stop hange the water and leave it as it is? Nitrites will climb sky high.
Letting the nitrites go higher really isn't a problem. I would stop doing the water changes and let the bacteria grow to remove the nitrites. pH number is good and your bacteria should thrive in that temp.
 

Troyboy

Member
I have a 55 gallon heading into week 3 of the cycle.
I'm having trouble keeping the ammonia level up. The tank is processing 3-4 ppm back to zero within 12 hours for the last week. Nitrites barely register (compared to an already established tank).
I realize the nitrite process is slow but should I add ammonia every 12 hours instead of 24 to keep levels at a constant 3-4 ppm until nitrite levels begin to climb?
 
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mattgirl

Member
Troyboy said:
I have a 55 gallon heading into week 3 of the cycle.
I'm having trouble keeping the ammonia level up. The tank is processing 3-4 ppm back to zero within 12 hours for the last week. Nitrites barely register (compared to an already established tank).
I realize the nitrite process is slow but should I add ammonia every 12 hours instead of 24 to keep levels at a constant 3-4 ppm until nitrite levels begin to climb?
Welcome to Fishlore

I wouldn't. It isn't at all unusual for it to take a good 3 weeks for the nitrites to spike. Continue adding ammonia each time it drops down to or very close to 0 but no more often than every 24 hours. There is no need to run your test any more often than every 24 hours either.

You said: Nitrites barely register ...... Do you mean nitrates? You shouldn't have any nitrites in an established tank. Since you mentioned an established tank. Do you already have a fully cycled tank?
 

Troyboy

Member
mattgirl said:
Welcome to Fishlore

I wouldn't. It isn't at all unusual for it to take a good 3 weeks for the nitrites to spike. Continue adding ammonia each time it drops down to or very close to 0 but no more often than every 24 hours. There is no need to run your test any more often than every 24 hours either.

You said: Nitrites barely register ...... Do you mean nitrates? You shouldn't have any nitrites in an established tank. Since you mentioned an established tank. Do you already have a fully cycled tank?
Yes Nitrites. I have a different already established tank and did a Nitrite test for both to get a side by side comparison. The Nitrite test for the established tank is a very light aquamarine color (API test kit) and the Nitrite test for the new tank is slightly darker but not into the purple range yet. I will stick to the 24 hour ammonia schedule and check things in a few more days. Thanks.
 
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mattgirl

Member
Troyboy said:
Yes Nitrites. I have a different already established tank and did a Nitrite test for both to get a side by side comparison. The Nitrite test for the established tank is a very light aquamarine color (API test kit) and the Nitrite test for the new tank is slightly darker but not into the purple range yet. I will stick to the 24 hour ammonia schedule and check things in a few more days. Thanks.
It is unusual to be seeing nitrites in a fully cycled tank so that has me scratching my head.

The main reason I asked if you have an established tank is if you do you can really speed up the cycle in the new tank by moving some bacteria from the cycled tank over to this one. Everything in the cycled tank will have bacteria on it. The strongest colony is going to be on the filter media but anything you can move over to this tank from that one will speed up the cycle in this one.
 

Troyboy

Member
mattgirl said:
It is unusual to be seeing nitrites in a fully cycled tank so that has me scratching my head.

The main reason I asked if you have an established tank is if you do you can really speed up the cycle in the new tank by moving some bacteria from the cycled tank over to this one. Everything in the cycled tank will have bacteria on it. The strongest colony is going to be on the filter media but anything you can move over to this tank from that one will speed up the cycle in this one.
Lol, I understand about the (lack of) Nitrites on the fully cycled tank. I just wanted a base comparison between the two tanks to see if I had any activity at all.
I did move over some of the media from the cycled tank to the new one. Maybe that's why it is cycling ammonia so quickly and I'll just have to patient for the rest to happen.
 
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mattgirl

Member
Troyboy said:
Lol, I understand about the (lack of) Nitrites on the fully cycled tank. I just wanted a base comparison between the two tanks to see if I had any activity at all.
I did move over some of the media from the cycled tank to the new one. Maybe that's why it is cycling ammonia so quickly and I'll just have to patient for the rest to happen.
Perfect. Moving bacteria from an established tank is the very best way to jump start a cycle but even then, patience is the one thing we have to have plenty of. By using the seeded media it is very possible you will not experience a huge spike in nitrites. If the ammonia is going down within 24 hours and you are seeing nitrates (you should be with the amount of ammonia this tank is processing) then your cycle is very close to done.
 

Troyboy

Member
mattgirl said:
Perfect. Moving bacteria from an established tank is the very best way to jump start a cycle but even then, patience is the one thing we have to have plenty of. By using the seeded media it is very possible you will not experience a huge spike in nitrites. If the ammonia is going down within 24 hours and you are seeing nitrates (you should be with the amount of ammonia this tank is processing) then your cycle is very close to done.
Ohhh, that's so good to know about a naturally seeded tank for the Nitrites. I was getting anxious.
I threw in some more media from the old tank in last night for good measure. Haven't tested for Nitrates in a while but it looks like they're up to a healthy 20ppm so I'll give it another week before blessing the tank with fish after a water change if all goes well.
 

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