Re: Can you over Chloinate?
With your cya levels you needed to have you FC levels b/t 5-10 ppm. You did the right thing by adding the borax to increase your ph, but I think it would have been best to do it in moderation, a couple pounds at a time.
Yes, you can add too much chlorine. You will bleach you liner(if you have a liner) if the levels get too high.
With your CYA level of 60 you need to keep your fc levels between 15-20ppm throughout the day and night until the algae is gone. Brushing the sides and vacuuming the bottom will help the process. Continue to add the borax as needed, a couple pounds at a time. Be careful though as the bleach may increase your ph as well.
See Ben's Best Guess Table for more info and download the bleach calculator(if you haven't already) as well. Plug in how many gallons your pool is and it will tell you how much bleach to add to get to a specific level.
Also read read read-knowledge is power There is a lot of excellent information available on this site to help you.
27ft 17K gallon Polytech aluminum & stainless AG Pool / DE filter / Wedding Cake Steps