What pH test are you using? Is it a liquid kit or test strips?
What the pH is when it exits the tap doesn't necessarily mean anything. After the water vents with the atmosphere your pH will almost certainly change. Your tap water contains dissolved CO2 which lowers pH. That will gas out. Measure the pH again after 24 hours and it will almost certainly 7 if you performed a large water change.
You don't want to increase your alkalinity/KH unless you need to. It might be fine. In any case, don't use any pH up or alkaline stabalizer, neutralizer or other of those products.
Crushed coral can be used very cautiously but you need to know and measure your KH if adding it.