kH and pH and Calcium problems

[Aquattro]

To answer your question, based on my experience, toss your pH tester away and don't worry about it. I haven't checked pH since 2004 or so...
Also, to avoid any large swings, don't let the values get that low before bumping them. Then everything will be happy

[Casey8]

You can add vinegar to lower the PH. Use 1ml vinegar per gallon will drop the PH by 0.3 units, that the way I had read it. You can google it to do some more research about this or read some of the articles from Randy Holmes about reef chemistry.