If I convert a established freshwater tank to a brackish tank will I have to cycle to tank again? Or will the bacteria be able to handle the change. I'm talking about maybe .10-.15.
Yes and no. If you change all in one day yes, but if you do it over a couple weeks, no. But if you do it over a couple weeks, basically you just cycled it. But a change of .1 everyday will not really hurt the bio cycle. Either way though, will take time.