Hmmm. Well, I have always been pretty aggressive with Cl but 9 gallons is a pretty big hit.....somewhere around 32-36ppm depending on how many gallons in your pool.

Did you calculate that prior to putting it in?

My bet is you'll still be fine because you've got so much junk in your pool. However, I think I'd back off that big of a dose next time....maybe cut that in half.....around 15ppm max.

On a positive note, that'll sure kill a lot of algae!! Don't be surprised if your filter pressure is waay up tomorrow. (and most of that Cl gone!) Just backwash it out and start again. As I posted earlier, the need to backwash will lessen as you clean out the goo.

Keep us posted as you progress. Add chlorine as often as you can....just don't add so much