Sure sounds like metal in the water which fell out and stained your pool when you shocked. The first thing is to get a set of water testing results taken with a drops-based kit and post them here. Make sure that the CYA and CC levels are reported along wiith FC, pH, TA, CH. Also, ask them to test for metals.
If you don't have a kit that can test for those things, for now, go to a reputable pool store and let them test for you but just don't let them sell you a bunch of stuff.
(You'll need a good test kit if you don't already have one. The one we recommend is the Taylor K-2006 or 2006C (same kit, larger bottle of some reagents). If you buy it through the Amazon link in my signature, the Pool Forum makes a little money on the sale which helps us keep this form online. Only buy if the seller is Amato Industries, however. Some other sellers are substituting the K-2005 which you do NOT want. )
Also, tell us the ingredients in sani-shock 2. Don't add anything else right now until you get us some good readings.
Let's find out if you have any algae or if all of this is metals related.
I would also suggest that you spend a couple of hours reading through many of the posts in the metals section of the forum. You'll find many threads dealing with this same type of situation, You'll probably have to log out before you'll be able to see the other forums.
Post your results and somebody here will help you go from there.
Welcome to the Pool Forum!
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