What To Do Next?

[Matt_]

Basically the Ammonia in my tank is being processed really fast now. But the Nitrites aren't at all. Am I meant to do a water change or not?
I'm on about the 3rd week in now, 90litre Fluval Roma tank.

 

[ox5477]

Just keep adding ammonia like you have been everyday. Check for nitrite about 2 or 3 hours after you add the ammonia. You should see nitrite being created...

Are you seeing nitrate concentrations rising? Cause if you are, then your cycled and ready to go

 

[SJ2K]

Never water change during a fishless cycle, only once the ENTIRE process is complete and your ready to add all your fish

 

[Matt_]

I'm getting off the chart Nitrite and Nitrate..is this good?

 

[ox5477]

Ok, well your getting nitrates so this is good as it means you have the two types of bacteria you need growing. Now, when you add ammonia, are you measuring it out to be 4 ppm or are you just putting in any amount? you need to add enough to make it 4-6ppm, no more, no less.

When your bacteria is able to process this 4ppm into nitrite and nitrate in less than 24 hours, then do a large wc (90% or more) and once the water comes back to temp, your can add your fish

 

[Matt_]

Well at the moment I'm adding about 1ppm-2ppm everyday..and the Nitrites arent going down..

 

[Matt_]

Just realised theres bright green algae growing on my ocean rock, looks like a bit of brown fluffy type algae too. Is this a good sign?

 

[waterdrop]

Never water change during a fishless cycle, only once the ENTIRE process is complete and your ready to add all your fish

except when your pH crashes to 6.0 (!)

 

[waterdrop]

Ok, well your getting nitrates so this is good as it means you have the two types of bacteria you need growing. Now, when you add ammonia, are you measuring it out to be 4 ppm or are you just putting in any amount? you need to add enough to make it 4-6ppm, no more, no less.

When your bacteria is able to process this 4ppm into nitrite and nitrate in less than 24 hours, then do a large wc (90% or more) and once the water comes back to temp, your can add your fish

Hi ox,

BTT and a number of us have been easing down just a little on the amount of ammonia add, just during the nitrite spike stage. So, adding back to 4-5ppm each time ammonia drops to 0ppm up until it is dropping within 10-12 hours and nitrites are spiking to 5.0+. Then we ease the adding down to 2-3ppm just for that period (RDD writes about doing this too, saying to just maintain the ammonia-oxidizing bacteria minimally during this phase, he writes it not in his article but in some other threads) so that it is easier to see from the nitrite tests whether anything is happening. Then as soon as nitrites begin dropping to zero also, we ease back up to adding 4-5ppm again for the final qualification of the biofilter.

That's why Matt is referring to adding only 2ppm - he's in his nitrite spike stage and is following this approach that RDD, BTT and I have written about.

Let us know what you think about it. I'm the first to say that perhaps we are missing something - perhaps it does more harm than good. The theory is that since 1ppm ammonia creates 2.7ppm nitrite then higher ammonia adds at the beginning of the nitrite spike stage just build up huge amounts of nitrite that can't be processed by the small population of nitrite processing bacteria at that early stage of their development - leading to a long period where you just keep receiving 5.0 as the feedback about nitrite. There is also an aspect of excess nitrites and nitrates tending to drive pH down in a stronger way. Anyway, several things. BTT is probably a better spokesperson about it than me.

~~waterdrop~~