Lonewolfblue, sounds like we may have the same water source. lol My tap has a gh of 2. The pH is good at 7ish, depending on the light, how tired my eyes are and oh, the moon phase when I try to match to the color chart.
I am also trying crushed coral in the filter. But, it had no effect till I gradually raised gh with epsom salt (mgso4) to around a gh of 9. Then it started to buffer. Guess my extrememly low gh was too much initially. It will be interesting to see how much is needed to finally stabilize it. And real interesting when I finally get an african cichlid tank up & running. And yes, Bill, it has advantages, but man if you don't harden it ....... the pH can crash if a fish so much as sneezes!!