Trying to cycle small 2.5g freshwater tank

[Tfat91]

Hello everyone,

I'm brand new to this forum, and just as new to fishkeeping, so please forgive my ignorance on both subjects! I'm currently trying to perform a fishless cycle for my 2.5g Aqueon Minibow. I filled the tank with some gravel/substrate, a small porcelain hollow rock cave, a live small amazon sword, and another fake plant which I may remove for space. Its running the factory filter that comes with the tank, along with an Aqueon Betta filter with Volcano bubbler.

My plan is to get a small betta for this tank which is why I was thinking about taking out the factory filter (current may be too strong) after establishing the tank with the volcano betta filter.

I had no idea about the nitrogen cycle before I was given this tank so I have been researching and trying to piece my way through. All tests performed using API freshwater master test kit. My tap water: 0 ammonia, 0 nitrite, 0 nitrate, ph 7.0. I used seachem prime to condition my water before filling the 2.5g tank

Start of cycle:
-1/8/22: started with 0 ammonia, 0 nitrite, 0 nitrates. ph 7.4-7.6: added entire 3.38oz bottle of tetra safestart plus
-1/10/22 added some fish food to start the cycle, water reading later that day: ammonia 4ppm, nitrite 0, nitrate 5ppm. 1/11/22-1/13/22 results were similar
-1/13/21- 1/14/21: ammonia 1ppm, nitrite, 0, nitrate 40-80ppm
(I wasn't home to test 1/15-1/16/22)
-1/17/21 ammonia .25-.50ppm, nitrite 0, nitrate 40-80ppm, ph 7.4
---At this point I was thinking maybe my cycle was nearing the end so I did a 1gallon water change, conditioned my water and added to the tank. Post water change test (1 hour later): ph 7.4, 0 nitrite, 0-0.25ppm ammonia, 20-40ppm nitrate. After, I added a pinch of fritz ammonium chloride powder and tested an hour later: ammonia was 4.0ppm (hoping this would disappear in 24 hours)
-24 hours later i tested on 1/18/21: 2-4ppm ammonia, 0 nitrite, nitrate 20-40ppm
-1/19/22 ammonia 1-2ppm, nitrite 0 ppm, 40-80 nitrate, ph 7.4

I have never seen nitrites during this cycle. I also used some 5in1 API test strips to see if those register any nitrites in the tank and they do not either.

Should I continue to watch my ammonia drop, and redose until it completely disappears within 24 hours? Is it possible that my nitrites are being eaten so fast i never register them on a test?
----(side note, as of today I'm returning the fritz ammonia chloride powder since its hard to properly dose such a small tank and purchasing Fritz Aquatics Fishless Fuel Ammonia Solution for Aquariums 2 oz, as recommend by Fritz website).

I understand patience is key for cycling but I just want to make sure I am heading in the right direction. Thank you for any feedback or assistance!

[ColdKoi]

You are likely not cycled, but you are seeing the start of it

Keep adding fish food or whatever you wish to use to bring the ammonia up to 2ppm. Once you see that ammonia level drop to 0 within 24h with 0 nitrites showing you have established a decent cycle. At that point nitrates will be high, so do a large water change before adding your fish.

I have only done fish-in cycles and have found that there’s only been a small window of time ~24h where nitrites have shown up on a test. Next day they’ve been down to untestable levels again

[Tfat91]

Thank you for the guidance!

I'm assuming that's what happened with my nitrites. I cant find any other explanation how nitrates appeared in such large numbers.

[Tfat91]

1-20-21 water test results
ammonia: .25-.50ppm (always hard to see the color difference)
nitrite: 0ppm
nitrate: 40-80ppm (again, hard to see difference between the API reds)

I added ammonia as per the instructions on the Fritz Fishless Fuel (12 drops total, 2 drops per us gallon) to get it to 2.0ppm

Retested on 1/21/22 8am
ammonia: 4ppm
nitrite: 0 ppm
nitrate:40-80ppm

Did the ammonia go up too much? Or is this okay to continue feeding the cycle. I plan to just test once a day now to see where my levels are, and add ammonia again once they drop under 1ppm

[Aiken Drum]

You should only be adding ammonia if it drops. If it doesnt drop, dont add more.

Test daily, if your ammonia drops below 1ppm then dose it back upto 2ppm. If you see 0.5ppm then add enough of your ammonium chloride to add 1.5ppm. If its 0ppm then dose the full 2ppm.

Once you are able to dose 2ppm ammonia and 24 hours later you see 0ppm ammonia and 0ppm nitrite you are cycled.

With your ammonia dont add any more ammonia until it drops below 1ppm.

[Tfat91]

Appreciate it. Looks like it took about 2 1/2 days for my ammonia to drop from 4ppm down to 0-0.25 (just measured ammonia now). I just dosed back up to 2ppm and will test again tomorrow.

[Aiken Drum]

Any nitrite?

[Tfat91]

Todays water test showed:
pH: 7.4
ammonia 0-0.25ppm
nitrite:0 ppm
nitrate 40-80ppm

This is before I dosed back to 2.0ppm ammonia.

I have not seen any nitrites during this fishless cycle.

[Aiken Drum]

That looks positive. Well done. Positive experience with tetra safestart.

[Tfat91]

Todays update:
ammonia: 0.5-1.0ppm
nitritre: 0ppm
nitrate: 40-80ppm

However, my pH dropped to 6, or lower (barely registering yellow on api master test kit) it was around 7.4 on 1/23/22, before redosed my ammonia. The ammonia went up to 4.0ppm after dosing and has been dropping since.

Any particular reason for a massive pH drop? Should I do a large water change and continue the cycle?

[Aiken Drum]

If your carbonate hardness (KH) is really low that could cause a pH crash. It could also cause your cycle to crash.

Carbonate hardness also known as buffering capacity, absorbs acid in the water. Once its gone there is nothing to prevent acids lowering the pH.

Carbonate hardness is mostly made up of alkalinity. Alkalinity is important in the cycling process, once its gone the beneficial bacteria can no longer consume ammonia.

Yes i would do a water change. If it is a KH issue a water change should replenish it somewhat. I would either speak to your water company or get a KH test and see if it is an issue.

[Tfat91]

Thank you for the quick response. I did a 70-80% water change, adding the appropriate amount of seachem prime per gallon, and retested.

ammonia: 0-0.25ppm
nitrite:0ppm
nitrate: 10-20ppm
pH: 7.0
kH: 40-80ppm (using API test strips)

This is the first time I have seen the pH crash during this fishless cycle. Should I dose up to 2.0ppm ammonia to see if I can get cycle back on track?

[Aiken Drum]

Originally Posted by Tfat91

Thank you for the quick response. I did a 70-80% water change, adding the appropriate amount of seachem prime per gallon, and retested.

ammonia: 0-0.25ppm
nitrite:0ppm
nitrate: 10-20ppm
pH: 7.0
kH: 40-80ppm (using API test strips)

This is the first time I have seen the pH crash during this fishless cycle. Should I dose up to 2.0ppm ammonia to see if I can get cycle back on track?

Yeah. I would do that.

Going forward, when your tank has fish in it etc, your regular water changes will replenish your KH and stop these pH fluctuations.

You didnt happen to do a KH test before the water change did you?

[Tfat91]

Unfortunately I did not and I was just thinking that I should have. I just added ammonia to get back to 2.0ppm and I'll be sure to test again this time tomorrow. It seems like my GH and KH are on the low end in general.

The test strips for measuring GH and KH are a bit unreliable so I will look into API liquid dropper GH and KH test kit.

[Tfat91]

Checked my numbers again today

545pm EST 1/27/22
ammonia 0-0.25ppm
nitrite: 0ppm
nitrate 10-20ppm
pH: 7.0-7.2
GH:30
KH:40

Looks like my tank successfully consumed 2.0ppm ammonia in about 20-24 hours. Close to, or at the end of the cycle?
I dosed more ammonia just now to see if it can cycle 2.0ppm ammonia again by this time tomorrow.

[ColdKoi]

I’d say you’re looking pretty good. Doesn’t hurt to dose ammonia another day or 2 to make sure things are 100%

Then just a water chance to reduce nitrates and I’d be confident in adding fish

[Tfat91]

So todays numbers:
1/28/22 6pm EST
ammonia 0.25-.50ppm
nitrite: 0ppm
nitrate: 40ppm
pH 6.4

My pH looks like it dropped from 7-7.2 down to 6.4. So my tank seems to be successfully cycling ammonia but my pH is dropping slightly over a 48 hour period.

Is it safe to say cycle complete, and my pH should stabilize with weekly water changes?

Or is there an underlying problem where my pH seems to be dropping. I have read that its normal for pH drops near the end of the cycle, but any feedback is appreciated!

[Aiken Drum]

The natural processes happening in your tank, like the nitrogen cycle, puts acid into the water. Carbonate hardness (KH) will absorb acid and prevent pH from dropping suddenly. But when KH is used up this buffering is lost. Under normal circumstances your regular water changes should be enough to replenish KH that is lost through these natural processes. However if your pH is crashing just 2 days after a water change this could indicate that these water changes arent going to be suffucient. Did you take another KH test?

You could add a piece of cuttlefish bone into your tank or a bag of crushed coral into your filter which would put a steady supply of KH into the water and prevent these pH crashes.

[Tfat91]

GH is 30ppm
KH is less than 40ppm, looks closer to 0 on the test strip.

As per cuttlefish bone or crushed coral, do you recommend one over the other for a
small 2.5g tank?

[Aiken Drum]

From recollection it takes 7ppm KH to denitrify 1ppm ammonia. Whats the KH of your tap water? When stocked your tank wont likely be producing the same amount of ammonia as you have been dosing to cycle it, so you may not have an issue as long as you do your water changes.

I presume your filter for a 2.5g doesnt have a lot of spare capacity, so maybe getting a piece of cuttlefish bone, breaking a bit off, hide it at the back of the tank, replace it when its gone. Shouldn't need replacing all that often.