What causes foamy water?

Answer 1

Many common pool chemicals cause foamy pool water. For example algaecide. However, the foaming should not be excessive. If you have a lot of foaming, it could be due to a hold in your return line.

Answer 2

It's from proteins in the water, oils from your skin, deodorants. You can purchase deformer to add to the water that was consolidate it. The skimmer will pull it out of the water and pull it through the filter.