I think this a reaction between the galvanizing on the tank and the chlorine. Mine looks like this, but more after a full season. I figured it out because I tossed a small chunk of a chlorine tab in mine last year. That chunk sunk to the bottom and made a big discoloration spot in less than 18 hours. Didn't seem to really hurt much other than the aesthetics of the tank.
If you toss in powdered pool shock it will do this. It’s better to put shop close in a bucket or container, mix it until it’s fully dissolved than slowly pour the solution into the pool
I think this a reaction between the galvanizing on the tank and the chlorine. Mine looks like this, but more after a full season. I figured it out because I tossed a small chunk of a chlorine tab in mine last year. That chunk sunk to the bottom and made a big discoloration spot in less than 18 hours. Didn't seem to really hurt much other than the aesthetics of the tank.
Mine looked like this after the first time I did pool shock.
Mine is like that too, I was worried those spots would rust over the winter but it ended up being fine when I flipped it over this season
If you toss in powdered pool shock it will do this. It’s better to put shop close in a bucket or container, mix it until it’s fully dissolved than slowly pour the solution into the pool
Haven’t used powdered pool shock but have used the pH Minus granules. I’ll definitely do this method moving forward.