Please Help :( PH Value Maintenance

[Fiona]

Hi all, I am a beginner in Shrimp-keeping and has just set up my tank. I am hoping to rear Sulawesi Shrimps and had design my tank the best of I could.

My tank contains 3 Sulawesi Snails (1 fully-grown adult and 2 newborns) with a Sulawesi Rock, Coral Sands and Bits..

However, I noticed that my water's PH Value isnt consistence.. It is always buffering from PH 7.7 to PH 8. Is there anything that I can do to stablize the PH Value? I have yet to add in Shrimps bcos of this.. (Dont dare)

My water temp is at 28.4 degrees.

Kindly advice. Thanks alot!!

[Solstice]

How big is your tank? What filtration system you using? What is the ph level that you are looking to achieve? How much water change do you do each time?