Ah, really? H20 Mike uses pH modifier and look at his rays, lol. We use it and it works wonders for us... even with the sickies while we do water changes. Hasn't been a problem yet. But I'm definitely down to do some more research on it. But you're right. It shouldn't be sudden. And good point about monitoring the tap water.
As far as the name of the pH modifier we use, Matt puts it in plastic sandwich baggies, so I'll have to wait until he gets home to get the name of it... if you would still like it and haven't been utterly freaked out about using it, ha.