1 more thing I do. My PH normally will only fluctuate one direction, and if I know my target range which for hydro is 5.6-5.9 depending on who you talk to, I can use this information to determine what part of my target range I want to adjust my PH to.
If my PH is always dropping, then I will make my PH adjustments towards the top end of my target range and sometimes taking it just past it, say to a 5.98, that way, as it fluctuates it has to go completely across your target zone.
If you PH to a 5.65 then when it fluctuates it will quickly be out of your target range.
Of course this is only a viable option if your fluctuations are predictable in the directions they will fluctuate