Sand turned black

[layna]

So I'm re-cycling my tank (fish free) and I went to check the water parameters today.

I noticed there was a bit of black in my play sand substrate, so I dug a little deeper and there under the surface sand was quite a bit of sand that had turned black.
I swished it around a little and removed the black sand, is this an anaerobic gas pocket?

I never seen it before until today, and if it is a gas pocket, can it effect tank cycling?

 

[Treagle]

I would guess it was his digisted food although I never experienced a gas pocket in my tank so I'm not 100% sure.

 

[CJ1981]

Did it smell bad?

It certainly sounds like a pocket. I would be inclined to scoop all the black sand out if not all the sand you have.

How deep is your sand layer? Try to get into the habit of 'stirring' your sand regularly to minimise the risk of pockets forming.

Is your Axolotl in the tank?

 

[layna]

No, hes never been in it as I'm trying to cycle it

Sometimes the ornaments smell a little bit but I just rinse them in a tub of tank water.

I've taken some sand out so it's not a deep, but I just wondered what it was and if it can affect cycling :O

 

[CJ1981]

Essentially it is a build up of toxic gases in your sand. Be careful once you put your Axolotl into the tank as if this reoccurs then escaping gases can actually kill your Axolotl

What are you using to cycle your tank? Have you put fish food or prawns or something in it? I would suspect something hinky has gotten into your sand causing the bacteria to go a bit mental and produce a whole heap of yuck. The sand surrounding it has to all intents and purposes rotted producing the gas bubble.

To prevent this reoccuring then as I said before get into the habit of raking your sand regularly to disturb/break up and pockets of nastiness before they get too bad.

 

[ZombieAxolotl]

What CJ said

If it wasn't an axie tank I would say get some burying snails or freshwater clams to naturally stir the substrate.

the only options in an axie tank are lower the amount of sand to under 1/2" deep
and/or get into the habit of stirring the sand on a weekly basis. Usually you can get into the habit of it when you do a water change.

 

[layna]

Well I cycled it originally, then for whatever reason the cycle crashed so ammonia was sky high and nitrite and nitrate were 0 again, having really high ammonia readings I've left the water to cycle by itself this time.
I've removed quite a bit of sand and mixed it all now but I just didn't know what it was :O

Thanks for replying guys