when does a water change become irrelevant

[Proteus]

Originally Posted by BlueTang<3

Not sure how many of you guys monitor orp, I can tell tho from that level when to do a water change it hovers around 340 about a day after a water change, naw is around 250 but once it recovers I watch it and when it starts to fall again I do a waterchange. I can notice if I leave it drop a little more things start going a little funny.

This is something that I've consider monitoring. But thought irrelevant. Ypu could control your orp to remedy this problem though I would wonder the cost vs wc