Fish-In Cycling - When To Water Change & How Much?

[Raticataticus]

So as some of you may already know, I have a 30L tank containing 1 Betta and 2 Mystery Snails.
 
I got the Betta as a surprise for my Birthday (thanks Mum) and I had nothing proper to house him in, hence we are now doing a fish-in cycle. Went into my LFS yesterday to complain about the lousy lights on the tank they'd sold me and walked out with a new adapter for the lights and 2 mystery snails. Oops.
 
I am wanting to know, at what point should I do water changes? At the moment I am doing around 20% every second day. My readings seem to be okay (nothing extreme or off the charts).
 
My current readings are:
 
Ammonia = 0ppm/0.25ppm but more on the side of 0.
 
Nitrites = 2.0ppm/5.0ppm (could be lower, it's nearly impossible to tell)
 
Nitrates = 5.0ppm
 
My last water change was done at this time yesterday.

 

[Ninjouzata]

What is your pH and the temperature of the water?
 
I think you'll want to bring the nitrites down to 0.5ppm ASAP though.

 

[Raticataticus]

What is your pH and the temperature of the water?
 
I think you'll want to bring the nitrites down to 0.5ppm ASAP though.

 
My pH is around 6.8 / 7.0
 
What % should I change to get it down?

 

[Ninjouzata]

If it's at 2.0 and you change 50% you'll be at 1.0, so I think you'll want to do 75%.
 
I can't remember the affects of pH on nitrite and ammonia so am trying to find that for you right now

 

[Raticataticus]

If it's at 2.0 and you change 50% you'll be at 1.0, so I think you'll want to do 75%.
 
I can't remember the affects of pH on nitrite and ammonia so am trying to find that for you right now

 
Well I just did 50%, I will wait a few minutes for the filter to mix it all up and then test again.

 

[Ninjouzata]

Alrighty. Sorry I can't find the info..did PM someone who knows though but don't think he'll be awake for a bit.

 

[Raticataticus]

If it's at 2.0 and you change 50% you'll be at 1.0, so I think you'll want to do 75%.
 
I can't remember the affects of pH on nitrite and ammonia so am trying to find that for you right now

 
Well I think I managed to get the nitrites down to around 1.0ppm. 
 
Ammonia and Nitrates still seems about the same.

 

[the_lock_man]

At a medium pH like yours, you can safely let your ammonia get to 0.75ppm, before doing a 50% change.
 
Nitrite, on the other hand, is toxic at all levels. You need to use salt to counteract the effects. Put in ½g of salt (standard sodium chloride), and remember that when you change 50% of the water, to add another ¼g. Don't let nitrite go over 1.25ppm, if it does, again do a 50% change (and top up the salt).
 
This will allow as much ammonia and nitrite as is safely possible, to allow the bacteria to grow as quickly as possible.
 
Keep testing daily, and doing water changes when necessary as per above. When you have gone a week seeing 0ppm ammonia and 0ppm nitrite, then change 90%+ of the water (just leave the betta barely enough to swim upright in), to get rid of the salt, and you are cycled.

 

[TwoTankAmin]

At  pH of 7.0 and an assumed water temp of 80F (26.6C) and a total ammonia reading on an API type kit of 2 ppm, the toxic NH3 in the water is .0131 ppm.  .02 or lower is very safe (even for many inverts). The danger line is at .05 ppm which takes 7.6 ppm of TA to produce in the OP's tank. I would be unlikely to change water for ammonia reasons until it was over 2 ppm at least and or if the fish showed signs of ammonia related problems. 
 
I would treat nitrite with chloride.
 
I would not have any inverts in a cycling tank as they are almost always more sensitive to ammonia than fish.