Go with 30-40 pounds of Blue Tilapia next year and you will likely see a large reduction in the muck after the algae is gone....I never suggest less than 10 pounds Tilapia, in even a small pond.

The minimum stocking rate I determined years ago in Ohio is 40# per acre for effective algae control, so at 1/4 acre, 10 pounds is your ponds minimum rate.

Your water does just look to have dissolved rock dust, likely calium and should clear on it's own in time.