Aeration strips carbon dioxide, which raises pH. But aeration LOWERS 'carbonics' => carbon dioxide + carbonic acid + bicarbonate + carbonates.

Essentially, alkalinity is that fraction of the 'carbonics' that is present as bicarbonates or carbonates. You can't easily remove those. BUT if you lower the pH, you shift some of the bicarbonates and carbonates into the form of carbonic acid + carbon dioxide.

In your case, reducing the alkalinity enable your pool water to begin dissolving the scale. But that, in turn, replenishes the alkalinity, and increases the calcium.

Since you're leaving for a few days, I'd re-orient the eyeballs to reduce aeration, let the pH drift up to a stable plateau, raise the chlorine level -- and then restart the process once you return.

Brushing 2x per day probably doesn't hurt anything, but it probably doesn't help that much, either. Once a day, or even once every 2 days is probably enough. It's unlikely the dissolution process is moving fast enough to warrant a 2x per day brushing.

Losing chlorine could be a result of dissolving some of the algae capsules, and exposing oxidizable algae to the chlorine.

I'll look at your chart data, and update your pool sig. info.