I am new to the site and hope someone can help me! The bottom of my in ground pool is very rough! Cut the bottom of my kids feet. It look likes dirt sitting on the bottom but it is stuck to the bottom. The pool store has sent a tech out and they are having trouble fixing it. It looks like metal fall out but is stuck to the bottom. I have tried metal magic, they have put 2 gallons of muratic acid in and nothing! Any help would be much appreciated!