The common causes of pool liner tar and swimming pool liner scum (also commonly called pool goo) are the following:
  1. Contaminants from suntan lotion, environmental pollution, and oils (organic) from each swimmer, contain or create a soil that seems to settle on swimming pool liners at the water level.
  2. On newer pool liners, a light coat of vinyl plasticizer may rise to the surface of the swimming pool liner.
  3. Cosmetics from swimmers and tanning oils are oxidized. Chlorine creates this oxidation, and as a result a waxy scum occurs.
  4. Substances contained in algaecides decay organic material like grass and leaves.

The following are ways to prevent pool scum and pool tar from forming on swimming pool liners: These tips apply to both above ground pool liners and in ground pool liners.
  1. Chlorinate every other day to 6.0 – 8.0 parts per million.
  2. Repeated and due diligent filter backwashing as often as possible within the constraints of proper pool maintenance.
  3. Keep your pH between 7.0 and 7.2.
  4. Try to avoid quaternary algaecides.