Hi, and welcome!!
The brown that formed after the initial chlorine shock was metal that precipitated out. By adding the metal out, it re-suspended the metals into the water, which is why it cleared so quickly. However, now you're dealing with a situation where you not only have metals but also have algae, so just adding the metal out isn't going to fix the problem--you also are going to need to shock the pool. I'm assuming your CYA level is 10, although I'm not sure how you got that number, since the drop-based tests don't distinguish levels less than 30 ppm, so you're going to need to shock the pool to 12 ppm and hold it there, filtering 24/7, in order to clear the pool. However, having chlorine that high will also cause the metals to drop out again, so as you raise your chlorine level, you're going to need to add metal out as needed to keep the water from turning brown. It will probably help if you can add your chlorine into or very close to the skimmer, so that if the metals do drop out, they'll drop onto your filter instead of into the pool.
Hope this helps
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