Cycle Stuck

[Cempa]

Hello,

I've been doing a fishless cycle for close to two months now. Originally I took some substrate from an established tank, stuck it in my sump. Within a week I had a nitrite spike. I kept dosing with Ammonia, making sure I did not exceed 5ppm in either Ammonia or Nitrite. The Ammonia seemed to have processed quicker and quicker as the cycle went along. I then added some additional filter media (lava rock) to my sump assuming the cycle was almost complete. Since adding this additional lava rock (I cleaned in chlorinated water, washed around, then added dechlorinator, then placed in sump) the cycle has seemed to stall. My aquarium has barely been processing Nitrite (it does but very slow for 3 weeks). Again, I make sure my Ammonia and Nitrite never exceed 5 ppm. I also regularly check Ph, it is constant at 8. At this point its been 3 weeks of having both Ammonia and Nitrite. I still add Ammonia as it does get processed. I have a bit of Nitrate 7.5ppm. Any ideas as to what is going on? I'm at a loss.. I would have thought even if I destablized the tank, it wouldn't take 3 weeks and still have ammonia. Especially given the first week seemed to be processing ammonia rather quickly..

 

[Cempa]

Aquarium: 75 gallon bare bottom tank
Filter: 20 gallon sump, 6 gallons of lava rock, homemade filter sock as mechanical. Flow is around 450 gph.

 

[TheWolfman]

My guess is that you overdid it with the ammonia and sterilized your tank. 5ppm of ammonia is pretty high to keep consistent and for the B.B. to process that at a consistent level is probably asking a lot from a new tank. Whenever I seed a new tank I usually just add the fish and monitor the parameters closely. Usually it’s insta cycled. I’ve never dosed ammonia into my tank before so I don’t have much experience in that department. If I’m doing i fishless cycle from scratch I will just throw some fish food in the tank to feed the cycle.

 

[Drstrangelove]

Imo, very little BB comes with the substrate when you move, depending on how it's handled. First, BB can easily be dislodged as the sand or gravel is jumbled around and moved. The BB will likely perish or be thrown out with the water. Second, while there is BB in the substrate, there isn't going to be a large proportion from that original tank unless you were using an UG or reverse UG filter.

Putting part or all of an undisturbed mature filter (e.g., bioballs, sponge, pad, floss) in a new filter rather than relying on transferred substrate, will probably give you more consistent and faster results, imo.

3 ppm of ammonia is the target people suggest. (I've accomplished it with less.) Too much ammonia will inhibit bacterial growth, so I'd reduce the target to 3 ppm.

2 months isn't actually unreasonable from scratch and you are showing nitrates, so I wouldn't describe it as stalled. As long as you continue to get growing nitrate readings, you're getting pretty close.

 

[Cempa]

I guess what I'm not understanding is that after two weeks of having nitrifying bacteria why can't it handle processing 2-3ppm Ammonia in 24 hours. Technically the colony should have grown to that level at this point? I'm more confused by this then obviously not having a nitrate colony at this point..

 

[Cempa]

Just to add, at the beginning I only had 4ppm Ammonia. Once I had Nitrite I maintained half of that (2ppm) Ammonia but made sure Nitrite did not exceed the toxic levels of 5ppm.

 

[Drstrangelove]

I kept dosing with Ammonia, making sure I did not exceed 5ppm in either Ammonia or Nitrite.

BB is inhibited by excessive nitrogen in the from of ammonia or nitrous acid, the latter being much more important than the former. And in both cases, nitrobacter being much more sensitive than nitrosomonas.

I then added some additional filter media (lava rock) to my sump assuming the cycle was almost complete. Since adding this additional lava rock (I cleaned in chlorinated water, washed around, then added dechlorinator, then placed in sump) the cycle has seemed to stall.

This description is confusing. What was cleaned with chlorinated water? The lava rock you added? The lava rock that was cycling in the sump? All the lava rock? How and where was the lava rock cleaned then added?

Was the original lava rock in the sump submerged before? Is it submerged now? Was it moved around in the process while you added new lava rock?

As an observation, the phrases "cleaned in chlorinated water" and "the cycled has seemed to stall" are worrisome when they appear in the same sentence. Chlorinated water efficiently exterminates nitrobacter and nitrosomonas bacteria.

My aquarium has barely been processing Nitrite (it does but very slow for 3 weeks).

Perhaps an indicator the BB is inhibited, but also typical of a "from scratch" cycling process.

Again, I make sure my Ammonia and Nitrite never exceed 5 ppm.

5 ppm is more than enough to inhibit nitrobacter.

I also regularly check Ph, it is constant at 8.

I'm skeptical. The nitrogen cycle should reduce pH in a closed system. How does pH remain constant in a closed system undergoing any nitrification?

At this point its been 3 weeks of having both Ammonia and Nitrite. I still add Ammonia as it does get processed. I have a bit of Nitrate 7.5ppm.

When did you measure the nitrate levels? How often? Once? Was it before or after you added the new chlorinated lava rock?

How did you measure the nitrate as 7.5 as opposed to 5 or 10? The common commercial nitrate tests I recall don't provide metrics down to 7 or 8, much less to the tenths in the reading?

Also, what temperature do you keep the tank? And are you testing with test strips or liquid tests? Can you post photos of the the tests?

 

[Drstrangelove]

Just to add, at the beginning I only had 4ppm Ammonia. Once I had Nitrite I maintained half of that (2ppm) Ammonia but made sure Nitrite did not exceed the toxic levels of 5ppm.

I don't how you can "maintain" a level of 2 ppm ammonia.

Are you saying that you were adding only 2 ppm per day, even if it declined to zero later that day, or are you checking all day long an adding ammonia every time it tests below 2 ppm? If the latter, how are you calculating how much ammonia to add when it's not 2 ppm?

 

[skjl47]

First, BB can easily be dislodged as the sand or gravel is jumbled around and moved. The BB will likely perish or be thrown out with the water

Hello; At least one authority has a different take on the bb being easily removed from surfaces. I will include a link to an article in which this is mentioned. Long article and the mention is brief.
My take has been that the bb form a bio-film on surfaces ("sessile" may be the term) . This film is supposed to be fairly tenacious. I am sure aggressive cleaning can scrub some or all of this film of bacteria away, but mild handling should not have much effect.

I do agree that a UGF will likely promote more bb colonies and that other substrate may only have active colonies near the surface where some water flow is present.

To the OP. Two things. One is if you had material from an established tank hen why did you try a "fishless cycle"? You had the stuff to start a quick cycle. All you should have needed to do is add fish slowly over a few weeks so the bb population can be able to adjust to the bio-load.

The other is this link is my reference and I find it useful. A long read and not all will be understood right away, but useful over time.
Aquarium cycling link


http://www.americanaquariumproducts.com/nitrogen_cycle.html

 

[Cempa]

This description is confusing. What was cleaned with chlorinated water? The lava rock you added? The lava rock that was cycling in the sump? All the lava rock? How and where was the lava rock cleaned then added?

Was the original lava rock in the sump submerged before? Is it submerged now? Was it moved around in the process while you added new lava rock?

As an observation, the phrases "cleaned in chlorinated water" and "the cycled has seemed to stall" are worrisome when they appear in the same sentence. Chlorinated water efficiently exterminates nitrobacter and nitrosomonas bacteria.

Sorry, I should have clarified more clearly. During the cycle, when I started seeing a quick drop in Ammonia, and some Nitrate, I added the second compartment in my DIY sump with more lava rock. Basically purchased, and rinsed in chlorinated water. Then placed in a pale with water conditioner, and added piece by piece into the second compartment. I did not touch the first compartment that was in place during the entire cycle. The stall happened shortly after this, but I did have high readings of Nitrite (possibly exceeding 5ppm) at the this time.

Perhaps an indicator the BB is inhibited, but also typical of a "from scratch" cycling process.

Yes, and this is my first cycle with a bare bottom tank of this size..

5 ppm is more than enough to inhibit nitrobacter.

I was under the assumption it was levels in excess of 5 ppm -good to know!

I'm skeptical. The nitrogen cycle should reduce pH in a closed system. How does pH remain constant in a closed system undergoing any nitrification?

Sorry, I'm not familiar with the chemistry, but it is still 8.2 as of today. My other parameters have changed as attached.

When did you measure the nitrate levels? How often? Once? Was it before or after you added the new chlorinated lava rock?

I check it periodically, maybe ever 3 days. I noticed nitrates prior to adding the additional lava rock into my second compartment. The nitrate levels have increased as of today.

How did you measure the nitrate as 7.5 as opposed to 5 or 10? The common commercial nitrate tests I recall don't provide metrics down to 7 or 8, much less to the tenths in the reading?

Rough guess based on colour, it was between the two shades.

Also, what temperature do you keep the tank? And are you testing with test strips or liquid tests? Can you post photos of the the tests?

Temperature is set for 82. I use the liquid API Master kit for fresh water. Expires in 2022. I've attached photos for test results as of today. I did a large water change based on everyone's suggestions of my parameters being too high. Since then, I've noticed my ammonia has begun to drop again, and my Nitrites have peaked, nitrates have also increased. Ph is still roughly 8.2. Based on the results today, it looks like the cycle is moving again!

Just as an update, I've converted to a fish in cycle. My ammonia has dropped even as I have been feeding 3x a day. Based on my water tests, should I do a 25% water change to lower the nitrite or is it still in the safe zone?