Interesting that you believe it's scale but visibly there is no change. Scale usually comes with some amount of color change. Before doing anything too drastic, I would lower the water level to expose the top step (if your ground isn't too saturated) and pour some muriatic acid directly on that exposed step. If it bubbles on that top-rough step, then it is calcium. If not, you have something else happening. If you confirm it's calcium-related, you might consider maintaining a slightly negative CSI level for a few months. You can find the CSI level of your chemistry on the
PoolMath APP. Other than that, probably physically standings/buffing. There is a no-drain acid wash, but that can be risky if not done properly.