pH Monitor & Water Change

Just received pH monitor yesterday which I ordered from eBay before Chinese New Year. All the way from Hong Kong.

Managed to install and test it. With information from friend in LAKU, the tap water in Miri is pH 8. My Aquarium reading is pH 8.6.

As Kelesa need water pH around 6.5 - 7.0, thus I get some online consultation, and removing coral chip and water change seems to be the best trial to bring down the pH.

After 20% water change, the pH comes to 7.36. I will try to do another water change in 2 - 3 days time and see if can further bring down the pH reading further.

Anyway, am trying to find pH buffer for calibration use later.