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Discussion Starter · #1 ·
I setup a 20g long on Sept. 18th with ADA Amazonia "New" soil. I planted the tank pretty heavily, I added Tetra Safe Start and then later Seachem Stability, and I also seeded the filter by adding some bio-media from an established tank.

And as of now I still can't tell whether my tank has even started the nitrogen cycle or not.

I have been testing the water since I setup the tank. The day after I setup the tank the ammonia was high, which is normal for the ADA soil since it leaches ammonia.

Thus, I was expecting the fishless nitrogen cycle to begin. However, the problem is I have never gotten a nitrite or nitrate reading. Both have always remained at 0 ppm.

I thought maybe the ammonia was so high that it was preventing the tank from cycling. I also thought maybe there was a contaminant in the water, so I did some major water changes.

As of today (24 days since the tank was setup) my water temp is 80F, ammonia is at .25 to 1.0 ppm, nitrite 0 ppm, nitrate, 0 ppm, ph 6.2-6.4 ppm.

When I started testing the water I noticed the ph was at 6.0 ppm or maybe even lower. My tap water ph tests at 7.8.

A few questions:

1. Can the ph of the tank be so low as to prevent the nitrogen cycle from starting?

2. Should I just do a few more water changes to drop the ammonia to 0 ppm and then add fish? I have read that at such a low ph as my tank has the ammonia is actually ammonium which is not toxic to fish.

3. Has anyone experienced anything similar?

4. Is it possible that I have established nitrite eating bacteria that are keeping the nitrites at 0 ppm? And at the same time have ammonia eating bacteria that are either non-existant or in low numbers because of the low ph.

Please let me know what you think? Any help is greatly appreciated.

Thanks.
 

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I setup a 20g long on Sept. 18th with ADA Amazonia "New" soil. I planted the tank pretty heavily, I added Tetra Safe Start and then later Seachem Stability, and I also seeded the filter by adding some bio-media from an established tank.

And as of now I still can't tell whether my tank has even started the nitrogen cycle or not.

I have been testing the water since I setup the tank. The day after I setup the tank the ammonia was high, which is normal for the ADA soil since it leaches ammonia.

Thus, I was expecting the fishless nitrogen cycle to begin. However, the problem is I have never gotten a nitrite or nitrate reading. Both have always remained at 0 ppm.

I thought maybe the ammonia was so high that it was preventing the tank from cycling. I also thought maybe there was a contaminant in the water, so I did some major water changes.

As of today (24 days since the tank was setup) my water temp is 80F, ammonia is at .25 to 1.0 ppm, nitrite 0 ppm, nitrate, 0 ppm, ph 6.2-6.4 ppm.

When I started testing the water I noticed the ph was at 6.0 ppm or maybe even lower. My tap water ph tests at 7.8.

A few questions:

1. Can the ph of the tank be so low as to prevent the nitrogen cycle from starting?

2. Should I just do a few more water changes to drop the ammonia to 0 ppm and then add fish? I have read that at such a low ph as my tank has the ammonia is actually ammonium which is not toxic to fish.

3. Has anyone experienced anything similar?

4. Is it possible that I have established nitrite eating bacteria that are keeping the nitrites at 0 ppm? And at the same time have ammonia eating bacteria that are either non-existant or in low numbers because of the low ph.

Please let me know what you think? Any help is greatly appreciated.

Thanks.
Yes, your pH probably has had a negative effect on your cycle. Below a pH of 6.5 nitrifying bacteria have difficulty in establishing a large enough colony to provide biological filtration. I had this same problem with a tank VERY recently, and once I bumped my pH up to about 6.9 the tank cycled within a week or so. I would probably add a few VERY hardy fish to your tank after your raise your pH and wait until it stabilizes before you add more. Or, you could continue with your fishless cycle and be patient, but after you raise that pH to maybe 6.9-7.1.

PS- pH is not read in ppm- it is a self-contained scale from 1 (acidic) to 14 (basic) with 7 being neutral. Your substrate will probably significantly lower your pH so you may need to buffer it.
 

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Good questions, and I have some thoughts though maybe not the total answer, as seems to be the case with many issues on this forum, keeps it interesting!

1. My understanding is that plants can, do, and in fact prefer to take up nitrogen in the ammonia form. Thus if you planted heavily, the plants are snacking on the nitrogen before the bacteria get a chance.
2. I have heard that the nitrogen bacteria will not do well at a pH below 6.4, I don't know if they die but they are not happy. Are you using tap water or RO water, if RO are you supplementing the GH and KH? These will act as a buffer and prevent highs and lows of pH shifts when running CO2 (with in reason).
3. Are you fertilizing? If there is luxury nutrients (i.e. more than the plants will need) especially of the nitrogen, then the bacteria will get a chance to get a foot hold. Not sure if this is true but it makes intuitive sense.
4. Get a fish, nothing says happy bacteria like fish poop.
5. I've always wondered about adding old tank water from another tank to a new tank for cycling...not sure if thats a good idea, likely not, but at least there would be bacteria in the water that are used to the conditions you are asking new ones to establish themselves in.
6. Possible you already have a population if you started with older biomedia in the filter.
 

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Discussion Starter · #4 ·
Good questions, and I have some thoughts though maybe not the total answer, as seems to be the case with many issues on this forum, keeps it interesting!

1. My understanding is that plants can, do, and in fact prefer to take up nitrogen in the ammonia form. Thus if you planted heavily, the plants are snacking on the nitrogen before the bacteria get a chance.
2. I have heard that the nitrogen bacteria will not do well at a pH below 6.4, I don't know if they die but they are not happy. Are you using tap water or RO water, if RO are you supplementing the GH and KH? These will act as a buffer and prevent highs and lows of pH shifts when running CO2 (with in reason). I am using tapwater. The tapwater ph is 7.6 or 7.8. I forget which one since I only tested it once. I'm not home to double check.
3. Are you fertilizing? If there is luxury nutrients (i.e. more than the plants will need) especially of the nitrogen, then the bacteria will get a chance to get a foot hold. Not sure if this is true but it makes intuitive sense. I am EI dosing.
4. Get a fish, nothing says happy bacteria like fish poop. The ADA soil is already leaching the ammonia into the water. Thus, allowing a fishless nitrogen cycle to start. Basically the ADA soil does what adding fish into the tank would do, introduce ammonia.
5. I've always wondered about adding old tank water from another tank to a new tank for cycling...not sure if thats a good idea, likely not, but at least there would be bacteria in the water that are used to the conditions you are asking new ones to establish themselves in.
6. Possible you already have a population if you started with older biomedia in the filter.
Answers are above in red.
 

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Discussion Starter · #5 ·
Yes, your pH probably has had a negative effect on your cycle. Below a pH of 6.5 nitrifying bacteria have difficulty in establishing a large enough colony to provide biological filtration. I had this same problem with a tank VERY recently, and once I bumped my pH up to about 6.9 the tank cycled within a week or so. I would probably add a few VERY hardy fish to your tank after your raise your pH and wait until it stabilizes before you add more. Or, you could continue with your fishless cycle and be patient, but after you raise that pH to maybe 6.9-7.1.

PS- pH is not read in ppm- it is a self-contained scale from 1 (acidic) to 14 (basic) with 7 being neutral. Your substrate will probably significantly lower your pH so you may need to buffer it.
To increas the ph in the tank:

Should I continue to do water changes until it has risen to 6.9-7/1 or should I add something to the tank to quickly raise the ph so that I can start the cycle?

There are no fish in the tank so I don't have to worry about ph swings killing fish. If I should use a product, which one would be the easiest and safest for the plants in the tank.
 

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Plant will utilize ammonia, but nitrates are easier for them. The plants are probably using the nitrates if the tank is heavily planted. If this is the case, when ammonia drops to 0ppm the tank is cycled.

Try not to use fish for cycling. Who wants to be poisoned for a month? The soil will leach all the ammonia you need. (not directed at the OP)
 

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To increas the ph in the tank:

Should I continue to do water changes until it has risen to 6.9-7/1 or should I add something to the tank to quickly raise the ph so that I can start the cycle?

There are no fish in the tank so I don't have to worry about ph swings killing fish. If I should use a product, which one would be the easiest and safest for the plants in the tank.
I wouldn't use products myself. It's just buying what nature will do for free.

If your ph is 7+ from the tap if the soil dropping the ph. Do water changes like you should any new tank, IMO. Every three days or so.
 
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