If you're going to change your PH level, I'd change the base and not chase the drop. The 2HR aquarist spread sheet on what PH level drops are needed vs PH/KH levels. You can find it HERE
Tbh with you, I myself have stopped chasing KH and PH levels. I run tap water on my 2 tanks currently. I used to remineralize RO water and eventually gave up. Also Sodium bicarbonate (baking soda) will raise KH/PH on the cheap.