Help! Pool is 7 years old. Black stains everywhere! It’s definitely not algae. It’s a vinyl liner in an above ground pool. Don’t know what to do!

JamesW

TFP Expert
Mar 2, 2011
15,501
Looks like black algae or something growing under the liner. Maybe a bacteria, mold or fungus.
 

JamesW

TFP Expert
Mar 2, 2011
15,501
I would try a SLAM and brushing to see if it clears up.

If not, you might need to replace the liner and remove the contamination beneath the liner.