when does a water change become irrelevant

[Proteus]

Originally Posted by Aquattro

I would then argue that controlling ORP with external influences is simply masking an underlying issue (to a degree). Again, it may extend the window, but not make it irrelevant.

Are you masking or remedying. If after a wc the orp goes down that's a imbalance.
My hottub for example users ozone to oxidize organics which means I don't have the chemical additives to remedy and also prolongs the time between cleaning

Truth told we would need a chemist to do a proper analysis of a tank before and after a wc to really find out the true story.