When to start water changes?

[rdefino]

My tank is 3weeks old, reading are getting better. When should I start water changes? And what readings does a water change affect in what way?

Thanks

 

[Atari]

What are your levels?

IMO you should do the first change when the cycle is finished, unless you have animals in there in which case you should be doing frequent changes to keep them alive.

 

[crage34]

ditto atari