Tearing Down Failed Fishless Cycle - How Thoroughly Does The Tank Need

[CherrySparkles]

So I've been trying to fishless-ly cycle my 12 gallon tank for 2 months now with no success, and am tearing it down.

The tank and everything that went into it were brand new when I got them.

History of failed cycle:
- Set up tank, rinsed everything thoroughly,
- Filled tank with water, added Prime
- Packed filter tray with bio media and a sponge filter
- Temp 82F
- Added a bacterial supplement (Fresh Aqua A (bacteria) and Fresh Aqua B (food for bacteria)). The bacterial supplement is made by a German company, and it is NOT an ammonia reducer, strictly a nitrifying bacteria supplement, and so it should be fine to use in a fishless cycle.
- Added some ammonia (ingredients: water and ammonium hydroxide) to bring the level to 2PPM and waited.
- pH: 7.4-8.2 (depending on when ammonia added, which made pH swing a bit)

Initially the ammonia dropped a bit, but then flatlined and wouldn't move for weeks. The water got a bit cloudy, and so I did a 25% water change. Nothing happened. A few weeks later, I did a 50% water change to try to get things going. Nothing happened. I tried dosing the bacteria supplement and food several times again, with no real change. At one point, a few weeks ago, the ammonia was dropping very slowly, but then suddenly stopped and rose again. I never forgot to add Prime.

As soon as I added the bacterial supplement, and for the rest of the time the tank was trying to cycle, the tank had a very "earthy" smell. Like wet dirt, which I thought was a good thing, but no cycling activity happened. The water itself even had this earthy smell to it, which I noticed when dumping out water change water. Nitrites never showed up.

Well now that it's been 2 months of this, and the ammonia hasn't dropped really at all, I've decided to tear the tank down, set it back up with an ammonia absorbing filter insert, and let my betta have it, un-cycled, for now.

So here are my questions:

Given the above TOTAL failure to cycle, do I need to bleach (and then thoroughly rinse) the tank out before adding my betta to it? (recall that the tank was new when I got it and has had no fish in it yet, only bacteria supplement...)

Currently, I've taken everything out, rinsed it well in non-dechlorinated tap water, and set it up again. The tank, and the gravel especially, seems to have a residual earthy smell, and when I cleaned the gravel, there were lots of tiny bits of debris in it. Can I just run some carbon in the filter and then let my fish have it, or do I need to bleach everything, and not just rinse it in tap water?

And if bleaching is necessary, can everything be cleaned using bleach? (acrylic aquarium, aquarium pump, silk plants, plastic-coated gravel, etc.)

Sorry for the lengthy post - any advice you can give is so appreciated! I'm really not sure when wrong here (but I'm looking at the bacteria supplement) as I've cycled tanks before and not had this issue ever. I have another tank that I'm going to try another fishless cycle with, but want to set this one up un-cycled for now.

 

[gazeddy]

you might want to either go again or do a fish in cycle with a few danios. dont use bleach ever in a tank. if your going fishless cycle go to 4ppm and try and get your hands on some mature filter media either from lfs or from a member on here on the list

 

[ellena]

Did you check your pH? Getting down towards 6 and a cycle will stall, although it sounds like yours never really got started
I think you could go fish in with 1 betta in a 12 gall, as long as you have test kits and are ready for the water changes. I've done fish ins with 2 bettas in 5 gall tanks.
You can use bleach, a weak solution, rinse very well and use double doses of dechlor for a few pre fish water changes.

 

[CherrySparkles]

Did you check your pH? Getting down towards 6 and a cycle will stall, although it sounds like yours never really got started
I think you could go fish in with 1 betta in a 12 gall, as long as you have test kits and are ready for the water changes. I've done fish ins with 2 bettas in 5 gall tanks.
You can use bleach, a weak solution, rinse very well and use double doses of dechlor for a few pre fish water changes.

We did watch the pH closely, testing every few days. And we had one of those live pH strips in the tank, though I don't trust them a ton. Anyway, the pH never took a nose dive, stayed between 7.4 and 8.2 (it rose when ammonia was added). I agree that the cycle never really started.

So you do think that a cleaning with bleach is a good idea before trying again? I'm paranoid that something gross could somehow be in the tank and preventing it from cycling, even though I'm super careful that nothing accidentally gets in the water, and that the tank hasn't had anything other than bacteria booster and ammonia added! (and Prime, but I don't suspect it...)

The tank looked crystal clear before I took it down - no patches of algae or anything else visibly growing.

I also might try doing a fish-in cycle later, since it's a relatively large body of water compared to the bio-load (as in I hope ammonia levels wouldn't rise so quickly that I couldn't comfortably control with water changes)