Why Aren't My Levels Going Down?

Okay. So I've posted before but I am confused.
When cycling my 10 gallon fish tank, my nitrites & nitrates levels were super high.
I did a few water changes to bring the levels down & shortly my fish tank was cycled.

Now today, I am cycling my 125 Gallon fish tank.
Nitrates & nitrites have both been present shortly after the 2nd week.
I'm at my 4th week & I made a huge water change this past saturday & it did almost nothing.
I did one water change Tuesday & Wednesday (almost 90%) & my levels were lowered tremendously. Well today, my nitrites & nitrates are both up again sky high.
Is this normal?
First was when all levels were present about 2 weeks ago.
Second will be nitrates & nitrites after the first water change.
3rd is nitrites after another water change
4th will be todays level.

 

What's your filter?

 

It would appear that there is a lot of ammonia going into the tank, and you have a big ammonia converting bacteria colony to convert that large amount of ammonia into nitrites. But then it would seem your nitrite converting bacteria colony is not yet large enough to convert all of the nitrites into nitrates. So you may want to reduce the amount of ammonia you are adding to the tank (assuming this is a fishless cycle) or you're just going to have to wait it out.

But try not to allow your nitrite level to get over 5ppm. Sometimes nitrite levels or 5ppm and over will actually inhibit the growth of the nitrite converting bacteria, therefore stalling your cycle.

 

What's your filter?

My filters are 2 fluval 406 canisters.

It would appear that there is a lot of ammonia going into the tank, and you have a big ammonia converting bacteria colony to convert that large amount of ammonia into nitrites. But then it would seem your nitrite converting bacteria colony is not yet large enough to convert all of the nitrites into nitrates. So you may want to reduce the amount of ammonia you are adding to the tank (assuming this is a fishless cycle) or you're just going to have to wait it out.

But try not to allow your nitrite level to get over 5ppm. Sometimes nitrite levels or 5ppm and over will actually inhibit the growth of the nitrite converting bacteria, therefore stalling your cycle.

My ammonia is processing in less than 24 hours. I'm only adding about 2 ppm or so.
That's exactly why I have been doing water changes cause I do not want my cycle to stall but its going to be very hard to do daily water changes due to my levels.

I'm wondering if it just needs more time to cycle, but I just don't know what to do to help it keep the levels down besides water changes.

 

It appears it does need more time to cycle, and their is really nothing you can do to keep the levels down other than water changes, or start using a bacteria additive.

 

It appears it does need more time to cycle, and their is really nothing you can do to keep the levels down other than water changes, or start using a bacteria additive.

Well, I am going to do a water change daily and give it about a week. And if not I will be back on this topic once more

 

I'm confused. Why are you trying to keep levels down? This is a fishless cycle, right? Sounds like you have you ammonia consuming bacteria and some nitrite but not enough. Just keep the ammonia consuming bacteria fed and wait for nitrite consumers to grow to where they clear it in a day. Why do water changes until then? I'm new too so maybe I'm missing something?

 

I'm confused. Why are you trying to keep levels down? This is a fishless cycle, right? Sounds like you have you ammonia consuming bacteria and some nitrite but not enough. Just keep the ammonia consuming bacteria fed and wait for nitrite consumers to grow to where they clear it in a day. Why do water changes until then? I'm new too so maybe I'm missing something?

I am trying to keep levels down because high nitrites and high nitrates can stall your cycle. This is a fishless cycle but I have had both nitrites and nitrates high for about 2 weeks now with no signal of them being processed.
I figured this is what was happening, but it may not be that it is stalled. It may be, like you stated, there is not sufficient bacteria to process it in a day, but like I said, I just don't want my cycle to stall so that is why I did some water changes.

 

At this point it is going to take time and patience, lots of patience. Since this is a fishless cycle and no lives are at stake if it were me I wouldn't do any more water changes for at least a week or maybe up to 10 days. Go ahead and add ammonia as needed to keep feeding the bacteria. I wouldn't let it get all the way down to zero but if it does just be sure to dose it right back up as soon as you see zero.

A completely cycled tank has to have a perfect balance between the amount of ammonia to feed nitrites and then to process smoothly all the way to nitrates. Right now it is off balance but given time it will find its balance. Unless something happens like forgetting one time to add untreated water to any part of the tank this tank will cycle. As long as it has an ammonia source it has no choice.

I remember one lady that couldn't figure out why her tank wouldn't cycle. Come to find out she was priming her HOB filter with untreated water each time she turned it off to do a water change. Each time she did that she killed all the bacteria she was working so hard to grow. This is one of the reasons we ask so many questions when someone is having problems cycling a tank.

 

At this point it is going to take time and patience, lots of patience. Since this is a fishless cycle and no lives are at stake if it were me I wouldn't do any more water changes for at least a week or maybe up to 10 days. Go ahead and add ammonia as needed to keep feeding the bacteria. I wouldn't let it get all the way down to zero but if it does just be sure to dose it right back up as soon as you see zero.

A completely cycled tank has to have a perfect balance between the amount of ammonia to feed nitrites and then to process smoothly all the way to nitrates. Right now it is off balance but given time it will find its balance. Unless something happens like forgetting one time to add untreated water to any part of the tank this tank will cycle. As long as it has an ammonia source it has no choice.

I remember one lady that couldn't figure out why her tank wouldn't cycle. Come to find out she was priming her HOB filter with untreated water each time she turned it off to do a water change. Each time she did that she killed all the bacteria she was working so hard to grow. This is one of the reasons we ask so many questions when someone is having problems cycling a tank.

Thanks so much! When I first started using my canisters, I filled it with primed water. Every time I have done a water change, I just unplug it and plug it (hopefully I am doing the right thing) & it automatically turns back on & runs.
But anyways, I think I have no choice. I just want to move my fish asap! I am going to follow your tips!

 

I actually don't turn off my filters during a water change. The intake tubes are low enough in the tank to be below the low water line even during a 40% water change. I might have to turn them off if I did a 50% but normally 50% isn't necessary.

Sometime it is those small things we fail to do or something we do that can prevent a successful cycle. As far as I can see you are doing every thing right so I have no doubt your tank will cycle in time.