lowering pH?

so i bought a “dragon stone” for my tank specifically because i saw that they’re inert and won’t change the water parameters, but i’ve realized what i bought wasn’t a true dragon stone because my pH in that tank went up by like .6 since i put it in the tank and my natural pH is already on the higher end so this is not ideal. i removed the rock, so is the best course of action here to let the pH slowly come back down to normal through regular weekly water changes or is there something else i should do? i know sudden pH changes are worse than a less than ideal but stable pH. the pH in the tank is now 8.4 and it has a betta, a mystery snail, and some neocaridina shrimp