Brown Dust Covering Everything?

[FingersofFish]

Hi,
 
I have a 70L planted aquarium, currently about 2 weeks into cycling with ammonia 3.0ppm ammonia down to 0 in 24 hours, Nitrite consistently above 5.0ppm and around 5ppm nitrate. No nitrites or Nitrates in my tap water. 
 
The Tank is lit for 7hours a day, LED lighting which i think i calculated to be equivalent to about 6w/L incandescent light, also have primitive CO2 bioreactor system and air pump. I have not yet started dosing ferts.
 
Tank has been crystal clear since day one apart from slime mould on the mopani wood which has now cleared, and some bacteria/mould growing in the corners of the tank.
 
Have come home today to notice a very fine brown powder (looks almost like specks of rust/paprika) covering absolute everything, I.e all over the rocks, wood, gravel, airlines and on the leaves of the plants. The water still appears to be pretty clear but slightly cloudier than usual.
 
I thought at first it may be brown algae, but from looking at pictures/troubleshooting on-line it doesn't really look anything like it.
 
Anyone have any idea.

 

[Mamashack]

That nitrIte seems a bit high especially if you've got nitrAtes too but I don't know enough about the nitrogen cycle to suggest why. 
The brown stuff looks like what you might see after a vigorous gravel clean when all the gubbins settles back down, but if you are still cycling that probably isn't the case unless you are recycling the tank and starting again?
Maybe someone with more experience than me could offer a better explanation.

 

[daizeUK]

The brown stuff looks like diatoms to me.
 
How many times have you dosed ammonia?

 

[508]

Probably diatoms. Should go away in some time.

 

[FingersofFish]

Working on the basis of Ammonia clealy below 0.75ppm and nitrite above 2.0ppm I have done two full doses (to make 3.0ppm), as of teting today it's now been 2 consecutive tests since the last dose and ammonia is back down to 0.25ppm...
 
I was going to give the snack dose today as if i'm following the cycling guide that would be the right thing to do... however i'm pessimistic as today is only day 14 on my cycle and it seems far too early.

 

[Mamashack]

Depends if you've used any mature media to kick-start the process.
If you've used gravel or filter medium from a mature tank then some of the bacteria will have a head start.

 

[daizeUK]

That sounds fine.  14 days is quite early but your readings seem on track so you should continue to follow the guide.
 
You said that 3.0ppm ammonia is down to zero in 24 hours which is why I wondered how many times you've been adding ammonia.  Typically  - generally this will only happen after several additions.  But now you say it has been two consecutive tests since adding ammonia so I guess it is taking longer than 24 hours?

 

[FingersofFish]

Sorry I meant that ammonia is down to 0.25ppm from 3.0 after 48 hours my mistake, I have only been testing every 48 hours so wouldnt know regarding 24.
 
I'm guessing the plants might be the reason why ammonia is dropping so rapidly compared to nitrite, along with the obvious fact that the ammona -> nitrite bacteria grow faster. However nitrite has been 5.0ppm + since about day 5 of the cycle.
 
I added Dose 2 (3.0ppm) on Thursday, had a reading of 3.0ppm 1 hour after the addition. Following this i tested on saturday (getting a reading of 0.25/0.50ppm) and again today, getting a reading of 0.00 - 0.25ppm again.
 
*Didnt believe the test on Saturday so i repeated it, got 0.25/0.50ppm twice.

 

[daizeUK]

Ok it looks like your cycle is progressing well.
 
Diatoms are a pain.  Very common in new setups and they supposedly clear up after a few weeks/months, although mine always take considerably longer to disappear.  The good news is they are easily wiped off and I would suggest wiping them off your plants at least to keep your plants in good health.

 

[FingersofFish]

Thanks for the advice, will make sure i do that, Now just to figure out what to do about ferts!