Tolerance in ph swings
I've often heard people refer to PH swings or an unstable ph, as something that can lead to various forms of algae, stunted plant growth, etc.
I'm wondering what is an acceptable PH swing? I have a PH controller and pressurized co2, and my target ph for my tank is 6.5 (while co2 is running). Is a swing between 6.45 and 6.55 lets say, over the course of two hours, acceptable? Does it need to be more precise than that? If not, what would you all consider to be a dangerous swing in PH? (during co2 running hours).