Fishless Cycle Taking Over 8 Weeks

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sunsetshark

Aquarium Advice Newbie
Joined
Apr 26, 2022
Messages
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I’m at the end of week 8 of cycling my 20 gal tank for an axolotl. I used seeded ceramic rings from my established betta tank. And my tank still isn’t cycled.

I started with dosing 4ppm ammonia (Dr. Tim’s) and checked the parameters just about every day. After a week or so, I saw a rise in nitrites and nitrates, but the ammonia never went down. I waited 7 weeks for any change and there was still no change in ammonia. After talking around, I decided to do a 50% water change to get the ammonia lower. After that, it’s been around 0.5-1ppm and I saw nitrite go from 0.25 to >5ppm within the days after the water change. It’s been a week now since the 50% water change and ammonia and nitrite both still haven’t budged at all (other than maybe nitrite going up? Not sure how to tell)
I’m not really understanding what I did wrong/why the cycle isn’t complete after 8 weeks. (I don’t mind waiting more, just worried I did something wrong since I’ve found nothing online about cycles taking longer than 8 weeks) Am I basically starting the timer over now that I’m seeing a bigger nitrite spike? Any idea how long it’ll take for the ammonia and nitrite to go down from this point? I have 2 filters (sponge and HOB) and plenty of ceramic rings for bacteria to grow on. (No substrate since the future axolotl will not be big enough yet) I’m at a loss. Any advice?

Parameters:

0.5-1.0ppm ammonia

5+ppm nitrite (not sure quite how high it is)

40ppm nitrate (color is hard to differentiate, might be 40-80)

7.6 pH
 
There are no timescales for cycling a tank. Cycling a tank takes as long as it takes. Can be a couple of weeks, typically 6 to 8 weeks, sometimes much longer. Every cycle will take its own course. You can do the exact same process on 2 identical tanks and they will take different lengths of time to complete.

Im not seeing anything significantly wrong in what you are doing. Using established filter media doesnt seem to have helped much, but that is the go to method to speed things up. You could try adding a bottled bacteria like Dr Tims One and Only or Tetra Safestart, that may help. Dialing up the water temperature can help, 83 to 87f (28 to 30c) is the sweetspot for developing beneficial bacteria.

Or, ditch fishless cycle and do a fish (axolotl) in.
 
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