black spots after shock

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Welcome! :wave: In many cases, discoloring immediately after the introduction of adding chlorine is a reaction with metals in the water (i.e. iron or copper). Please answer the following to help:
- How are you testing your water?
- Can you post a full set of test results?
- Are you on a well?
- How do you normally chlorinate your water each day?
- Update your signature with all of your pool and equipment info. Include the test kit and type of pool.

This info will help get us started.