Can very low GH stall a cycle?

angsess78

I have been cycling for a month. Started fish in, but due to some bad advice lost the 4 fish. My tank readily consumes 1ppm ammonia in 24 hrs, but both nitrites and nitrates end up through the roof. It has been in this state for 2 weeks at this point. I have tried water changing to get the levels down like is suggested in the stalled cycle sticky but it did not help. It talks about depleted minerals in the water being an issue so I am wondering if the fact that the GH test only takes 1 drop could be a factor? My KH test is 8 drops, and pH stays stable at 7.5, not matter what happens to other numbers.
 

jdhef

The only time I cycled without using Tetra SafeStart, It took 3 weeks to get thru the ammonia phase, and then 3 additional weeks to get thru the nitrite phase. So it sounds to me like everything is on track.
 

mattgirl

I am assuming you are now doing a fishless cycle. Please correct me if I am wrong. If both nitrites and nitrates are through the roof I have to think you haven't changed out enough water. Change out enough to get the numbers down to reasonable levels.
 

angsess78

I am assuming you are now doing a fishless cycle. Please correct me if I am wrong. If both nitrites and nitrates are through the roof I have to think you haven't changed out enough water. Change out enough to get the numbers down to reasonable levels.
I am doing fishless. I have done water changes, and the readings just shoot right back up. Last water change was Friday afternoon. After the change ammonia read 0 nitrites read 0.25 ppm and nitrates less than 5 ppm. I added 1 ppm of ammonia after the water change, and within 24 hrs ammonia was gone and nitrites were right at 2 ppm, nitrates about 20. Added another ppm of ammonia. Last night, 0 ammonia, nitrites were dark purple to the point that i feel like it was off the scale, and Nitrates were 40 at least, but not quite as red as the 80. So I am headed to the point where everything is off the scale again.
The only time I cycled without using Tetra SafeStart, It took 3 weeks to get thru the ammonia phase, and then 3 additional weeks to get thru the nitrite phase. So it sounds to me like everything is on track.
I have used a full bottle of fluval cycle when i started, and added tetra safe start on Saturday, 24 hrs after doing a water change because my readings were so high.
 

mattgirl

It sounds like your cycle is doing what it is supposed to do. As long as the ammonia you are adding is going down to 0 within 24 hours your cycle is moving forward. As long as the pH stays up where it is and the ammonia is going down the high nitrites and nitrates shouldn't be a problem so don't worry about keeping them down. If the ammonia stops going down it will be time to do a water change. Since this is a fisless cycle don't bother with small water changes. If the ammonia stops going down or the pH crashes change out no less than 75% of the water.

As long as the ammonia is going down I wouldn't even be running the nitrate test. We know you have both ammonia and nitrite eating bacteria. You just don't have quite enough to clear out all of the nitrites. Just feed the bacteria and give it time.

Since you already have both ammonia and nitrite eating bacteria I'm not sure the TSS was needed but fortunately it shouldn't hurt anything and may still help.

At this point I would only be adding ammonia every other day. This will slow down the production of nitrites and will give the bacteria a chance to catch up.
 

Bwood22

How often are you dosing ammonia?
These are rough numbers, but for every 1ppm of ammonia you get about 3ppm nitrite -> 4ppm nitrate.

If your nitrite and nitrate readings are thru the roof, its ok to back off on the ammonia a bit.
Your nitrosomonas (the bacteria that converts ammonia to nitrite) are not going to starve if you don't feed them daily.

Also keeping your nitrite concentration below 5ppm is important because if it rises above that it becomes toxic to the nitrobacter (the bacteria responsible for converting nitrite into nitrate) that you are trying to grow.

My recommendation would be to dose your ammonia and wait 24hours for it to all convert. Then change enough water until your nitrite is measurable. The exact nitrite ppm doesn't matter right now as long as its below 5 and its not off the chart.

Now monitor that nitrite level over the next 3 days to see if or how much it drops.

Then after those 3 days dose some more ammonia and do it all over again.

Soon you will see that nitrite dropping significantly on its own and the water changes won't be needed to dilute the nitrite level anymore.

Doing this is also going to keep your nitrate levels down so your tank isn't completely nasty when your cycle is complete.

When you dose the ammonia and 24 hours later its all converted to nitrate you are good to go.
 

angsess78

So is Nitrite above 5ppm is toxic to nitorbacter? If that's the case then I think that may be my issue. I don't think its staying low enough long enough to build a colony.
 

Bwood22

So is Nitrite above 5ppm is toxic to nitorbacter? If that's the case then I think that may be my issue. I don't think its staying low enough long enough to build a colony.
Yeah, you definitely want to keep it diluted so that you can at least measure it.

You are on the right track but I would switch up your rhythm a bit.

-Dose ammonia
-wait 24 hours then dilute nitrite (water change)
- wait 3 days (test nitrite each day)
- repeat


A few other things to note that i think might be worth mentioning here. To answer your original question about low GH. I have not read the reference that you are referring to but I can see why one would say that mineral depleted water could stall a cycle.
Chemolithoautotrophs, like bacteria of the nitrosomonas and nitrobacter genus, utilize ammonia and nitrite respectively as an energy source and carbon dioxide for growth. There's not really anything else besides oxygen that they need. And since you have been doing water changes, your water hasn't gone stale and definitely is not depleted of these things.

It is also important to keep your PH stable. Here's why. The current bacteria that you have growing in your tank right now are bacteria that particularly like the PH of your water.
There are many varieties of nitrifying bacteria that grow and thrive at different PH levels.
So if your PH were to drop to about 6...some might argue that that will "stall" or "stop" your cycle, and for the most part....that's true.
So how do people keep soft water/low PH aquariums? Are they not cycled? Well of course they are, its just a different species of nitrosomonas and nitrobacter that thrive in that water. So while your current bacteria would die off if your PH were to drop....a new colony of bacteria would start to grow.

I really hope this helps give you a grasp of what's happening at a microscopic level.
Again I think you are almost there...just keep at it.
 

mattgirl

So is Nitrite above 5ppm is toxic to nitorbacter? If that's the case then I think that may be my issue. I don't think its staying low enough long enough to build a colony.
I know I keep reading this but I have helped a lot of folks cycle their tanks and this hasn't proven to be true.
 

Bwood22

I know I keep reading this but I have helped a lot of folks cycle their tanks and this hasn't proven to be true.
You know now that you mention it....I agree with you. I don't think I have ever seen that confirmed either. But I know that I can cycle a tank faster by following the steps that I reccomend vs just waiting it out. And the tank is much cleaner too.

Therefore I assumed that what I said about nitrites becoming toxic at high levels was true based on my experience and my results and probably reading it in alot of the same places as yourself.

Actually....something else was happening when I applied my method and Ive just learned why.....like just now.

Thank you for mattgirl for challenging that fact.

I still stand behind my recommendation. Here's why...I have just confirmed that high nitrite concentration does NOT inhibit nitrobacter activity, but high nitrate levels do. (High ammonia levels also inhibit nitrobacter activity but low ammonia levels actually help)

Here is an excerpt from PubMed Central (PMC).
PubMed Central is a journal managed by the National Center for Biotechnology Information (NCBI):

"...The nitrite-oxidizing activity of ZS-1 started to be inhibited by ammonia and nitrate when the concentrations of ammonia and nitrate reached 25 mg L−1 and 100 mg L−1, respectively. The inhibition was stronger with higher concentration of ammonia or nitrate. The nitrite-oxidizing activity of ZS-1, however, was not inhibited by high concentration of nitrite (500 mg L−1). The nitrite-oxidizing activity of ZS-1 was increased by low ammonia concentration (1 mg L−1 to 10 mg L−1)."

So...this article is specifically talking about ZS-1, Nitrobacter winogradskyi, which was also stated in the article that had an optimal PH of 7-9 and optimal temperature of 77-89 F.

So the method that I previously suggested will still work and help the process not only to cycle more quickly but also to not end up in a nitrate cesspool once it finally completes.

Here was one of my recent tanks at the very end of its cycle:


20210508_002920.jpg


Hope this helps lots of folks.....I think new information is awesome!
So is Nitrite above 5ppm is toxic to nitorbacter? If that's the case then I think that may be my issue. I don't think its staying low enough long enough to build a colony.
I wanted you to see this correction. Its the nitrate level that needs to be diluted. My apologies. Everything else holds true.
 

angsess78

You know now that you mention it....I agree with you. I don't think I have ever seen that confirmed either. But I know that I can cycle a tank faster by following the steps that I reccomend vs just waiting it out. And the tank is much cleaner too.

Therefore I assumed that what I said about nitrites becoming toxic at high levels was true based on my experience and my results and probably reading it in alot of the same places as yourself.

Actually....something else was happening when I applied my method and Ive just learned why.....like just now.

Thank you for mattgirl for challenging that fact.

I still stand behind my recommendation. Here's why...I have just confirmed that high nitrite concentration does NOT inhibit nitrobacter activity, but high nitrate levels do. (High ammonia levels also inhibit nitrobacter activity but low ammonia levels actually help)

Here is an excerpt from PubMed Central (PMC).
PubMed Central is a journal managed by the National Center for Biotechnology Information (NCBI):

"...The nitrite-oxidizing activity of ZS-1 started to be inhibited by ammonia and nitrate when the concentrations of ammonia and nitrate reached 25 mg L−1 and 100 mg L−1, respectively. The inhibition was stronger with higher concentration of ammonia or nitrate. The nitrite-oxidizing activity of ZS-1, however, was not inhibited by high concentration of nitrite (500 mg L−1). The nitrite-oxidizing activity of ZS-1 was increased by low ammonia concentration (1 mg L−1 to 10 mg L−1)."

So...this article is specifically talking about ZS-1, Nitrobacter winogradskyi, which was also stated in the article that had an optimal PH of 7-9 and optimal temperature of 77-89 F.

So the method that I previously suggested will still work and help the process not only to cycle more quickly but also to not end up in a nitrate cesspool once it finally completes.

Here was one of my recent tanks at the very end of its cycle:


20210508_002920.jpg


Hope this helps lots of folks.....I think new information is awesome!

I wanted you to see this correction. Its the nitrate level that needs to be diluted. My apologies. Everything else holds true.
Thanks for the correction and the source. From my limited microbiology knowledge this makes more sense. I will be attempting your method, starting with a water change tonight.
 

Bwood22

Thanks for the correction and the source. From my limited microbiology knowledge this makes more sense. I will be attempting your method, starting with a water change tonight.
Let us know how it goes! I'm anxious to hear back.
 

angsess78

Let us know how it goes! I'm anxious to hear back.
Got Nitrites down to 0.25 ppm with about a 75% water change. Ammonia at 0 nitrates at between 5 and 10. I left it alone and did not add ammonia. I will test again tonight and report back.
 

JeremyW

I don't know about nitrite or nitrate toxicity. I'm not a biologist or a chemist. But I am an engineer. And one thing I do understand is the importance of testing, and working with good data.

If you can't test it, you can't control it. If something is wrong, you can't tell. If something is right, you can't tell. Without testing, you are working blind. And if you are working outside the range of your test kit, well then you aren't really testing anything are you?

I strongly recommend keeping all levels down to concentrations that are easily measured by the test kits. In my opinion as soon as you can't tell what you have, you should do a water change. Concentrations of 2ppm ammonia and nitrite are easy to measure and are more than enough to cycle your tank.

So maybe nitrite gets toxic for the bacteria after 5ppm, or maybe it doesn't. But from a practical perspective, who cares? In my experience, there isn't a good reason for our levels to ever be high enough that toxicity to bacteria is even part of the conversation. Do the water changes, and keep your levels comfortably on the chart, and you won't have to worry about all the crazy stuff that happens off the chart.
 

Bwood22

Got Nitrites down to 0.25 ppm with about a 75% water change. Ammonia at 0 nitrates at between 5 and 10. I left it alone and did not add ammonia. I will test again tonight and

I don't know about nitrite or nitrate toxicity. I'm not a biologist or a chemist. But I am an engineer. And one thing I do understand is the importance of testing, and working with good data.

If you can't test it, you can't control it. If something is wrong, you can't tell. If something is right, you can't tell. Without testing, you are working blind. And if you are working outside the range of your test kit, well then you aren't really testing anything are you?

I strongly recommend keeping all levels down to concentrations that are easily measured by the test kits. In my opinion as soon as you can't tell what you have, you should do a water change. Concentrations of 2ppm ammonia and nitrite are easy to measure and are more than enough to cycle your tank.

So maybe nitrite gets toxic for the bacteria after 5ppm, or maybe it doesn't. But from a practical perspective, who cares? In my experience, there isn't a good reason for our levels to ever be high enough that toxicity to bacteria is even part of the conversation. Do the water changes, and keep your levels comfortably on the chart, and you won't have to worry about all the crazy stuff that happens off the chart.
Well said.
 

mattgirl

I do agree JeremyW The main thing I try to do is keep folks calm. Once we start telling folks new to the hobby high numbers are going cause big problems we send them into freak out mode. I do agree keeping things more balanced is the better option but if they are not while doing a fishless cycle no fish are being harmed and the tank will still cycle.

Neither high nitrites nor high nitrates alone are going to be detrimental to the cycling process but I do recommend doing a water changes to get and keep them down to reasonable levels. It takes a combination of things being out of balance to slow or stall a cycle. The majority of the time the stall is caused by a pH crash. I do question what caused the pH crash to begin with but in most cases a water change is all that needs to be done. It gets the pH back up and replenishes the minerals needed to keep it up. Unfortunately lots of folks fear doing water changes until they realize they are not removing bacteria when doing one.
 

angsess78

All helpful information folks! I will update with tonight's numbers when I get home




Today’s numbers:
ammonia 0
nitrites 0
nitrate 10

dosed with 1 ppm ammonia and we will see how it processes in the next 24 hours. I am encouraged by tonight’s numbers!
 

angsess78

last night:
ammonia 0
nitrite 2 ppm
nitrate between 20 and 40 ppm

I am letting it ride and will let you know how it goes.

Based on the numbers I am making the assumption that it is processing some nitrite into nitrate, correct? It would have to for the nitrate numbers to be rising at the rate they are?

FYI- my plants are absolutely thriving in the tank. I have tons of new growth and no algae.
 

Bwood22

You're almost there. And yes the nitrite is converting but the bacteria colony hasn't grown to a point where it can adequately handle the supply of food (nitrite) being produced based on the amount of ammonia you are dosing.
Which was 1ppm right?

2ppm nitrite and 5ppm nitrite are very close in color on the chart.
Something I've done before was to fill the vial with 2.5ml of tank water and the other 2.5ml of tap water then rerun the nitrite test.
If the test result color is still close to the high end nitrite color then you know that your nitrite level is indeed really high.
But...if you do this 50% diluted nitrite test and your results come back lighter purple, then that means that your nitrite level isn't so bad.
If you run those 2 nitrite tests daily, you should be able to see daily progress in your nitrite reduction. Pretty soon you will only need to run one test because your nitrite is sub 2ppm and its easier to read.
 

angsess78

You're almost there. And yes the nitrite is converting but the bacteria colony hasn't grown to a point where it can adequately handle the supply of food (nitrite) being produced based on the amount of ammonia you are dosing.
Which was 1ppm right?

2ppm nitrite and 5ppm nitrite are very close in color on the chart.
Something I've done before was to fill the vial with 2.5ml of tank water and the other 2.5ml of tap water then rerun the nitrite test.
If the test result color is still close to the high end nitrite color then you know that your nitrite level is indeed really high.
But...if you do this 50% diluted nitrite test and your results come back lighter purple, then that means that your nitrite level isn't so bad.
If you run those 2 nitrite tests daily, you should be able to see daily progress in your nitrite reduction. Pretty soon you will only need to run one test because your nitrite is sub 2ppm and its easier to read.
yes, 2 and 5 are really close, but last night's test was just a bit lighter than 2 so I think I was right at 2 ppm. I will definitely try a dilution though to see what that tells me. As I said I am going to let it ride for a couple of days and that would be a good way to track the drop off in Nitrite.
 

Bwood22

Awesome, keep me posted.
 

angsess78

I think we are turning the corner.
ammonia 0
nitrite 0.25 ( without diluting )
nitrate right at 20
 

Bwood22

I think we are turning the corner.
ammonia 0
nitrite 0.25 ( without diluting )
nitrate right at 20
YES!
 

angsess78

Just wanted to update. After Thursday nights test I added a ppm of ammonia. It took until this morning, so 36 hours, to clear completely of nitrites so I think we are really close. Do you guys think I should continue to dose, or add a small number of fish. I am thinking my first addition will be 8 cherry barbs. Do you think I am safe or should I give it a few more days?
 

StarGirl

Just wanted to update. After Thursday nights test I added a ppm of ammonia. It took until this morning, so 36 hours, to clear completely of nitrites so I think we are really close. Do you guys think I should continue to dose, or add a small number of fish. I am thinking my first addition will be 8 cherry barbs. Do you think I am safe or should I give it a few more days?
I would wait for fish until you see no nitrites at all. Keep dosing until that happens and then you should be good. :)
 

angsess78

I would wait for fish until you see no nitrites at all. Keep dosing until that happens and then you should be good. :)
I have no nitrites this morning after adding ammonia late Thursday night. Should I still wait?
 

StarGirl

How fast did it process the ammonia? I would still wait until I know I am for sure clear of Nitrites myself. You could just do a big water change and get your fish. You would just have to be ready to do water changes if anything spikes on you. Do you have Prime on hand?
 

Bwood22

I have no nitrites this morning after adding ammonia late Thursday night. Should I still wait?
You are so close...i know its hard but you are almost there. Dose ammonia wait 24 hours....if everything is converted to nitrate then go get your fish.
If not...just keep at it. It will get faster and faster. Next time i bet it doesn't take 36 hours to clear.
 

angsess78

How fast did it process the ammonia? I would still wait until I know I am for sure clear of Nitrites myself. You could just do a big water change and get your fish. You would just have to be ready to do water changes if anything spikes on you. Do you have Prime on hand?
Prime on hand. I always use it when I change water. It took right at 36 hours to completely clear 1 ppm Ammonia. Last night there was zero ammonia and 0.5 ppm nitrite 20 ppm nitrate. This morning 0 ammonia, 0 nitrite, just over 20 nitrate.
 

StarGirl

Prime on hand. I always use it when I change water. It took right at 36 hours to completely clear 1 ppm Ammonia. Last night there was zero ammonia and 0.5 ppm nitrite 20 ppm nitrate. This morning 0 ammonia, 0 nitrite, just over 20 nitrate.
Yeah wait until ammonia is gone in 24 hours and no nitrite at all. Soon I promise! ;)
 

angsess78

Ok. I dosed in to 1ppm ammonia. We will see where we are tomorrow
 

angsess78

Still not there. 24 hr numbers
0.25 ppm ammonia
2 ppm nitrite
40 ppm nitrate
will check it gains in 12 hours
 

angsess78

36 hour results
0 ammonia
0 nitrite
20 nitrate

dosed to 1ppm ammonia and will check in 24 hrs.
 

Bwood22

36 hour results
0 ammonia
0 nitrite
20 nitrate

dosed to 1ppm ammonia and will check in 24 hrs.
Hey....why did the nitrate drop?
 

angsess78

Hey....why did the nitrate drop?
I am thinking my plants. It is heavily planted and they are growing like crazy.
 

angsess78

Just wanted to report back. It is still taking more than for me to see nitrites drop to zero. Last night I had zero ammonia just under 2 ppm nitrite and 40 ppm nitrate 24hrs after dosing 1 pmm ammonia. If the pattern holds, by the time i get home to check we will be at zero nitrites. Should I continue to does to 1 ppm ammonia every time they drop to zero and wait it out, or is it time for a new strategy?
 

Bwood22

Just wanted to report back. It is still taking more than for me to see nitrites drop to zero. Last night I had zero ammonia just under 2 ppm nitrite and 40 ppm nitrate 24hrs after dosing 1 pmm ammonia. If the pattern holds, by the time i get home to check we will be at zero nitrites. Should I continue to does to 1 ppm ammonia every time they drop to zero and wait it out, or is it time for a new strategy?
Slow and steady wins the race. Keep doing what you're doing.
What is your nitrate level? If its really high, change a bunch of water before you dose ammonia again.
Other than that, don't switch up the routine.
 

angsess78

Slow and steady wins the race. Keep doing what you're doing.
What is your nitrate level? If its really high, change a bunch of water before you dose ammonia again.
Other than that, don't switch up the routine.
sorry, I just saw this. Nitrate levels stay between 20 and 40. I think my plants are helping to control that. They are growing like crazy.

Still working on establishing the cycle, but I think things are getting better. The nitrite test seems to be a little less purple at 24 hrs, and is still zero by 36 hours.
 

angsess78

I finally got a cycle! 24 hrs, zero ammonia, zero nitrite, 20 Nitrate between last night and today. Going to get some fish! I am going to do 6 bronze corydora to start.LFS has some nice looking juveniles.
 

Bwood22

I finally got a cycle! 24 hrs, zero ammonia, zero nitrite, 20 Nitrate between last night and today. Going to get some fish! I am going to do 6 bronze corydora to start.LFS has some nice looking juveniles.
Yes! Bout time!
 

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