Answer:

Suds or foam can be caused by several factors so how to address it depends on what is causing it. High pH and or high total alkalinity can cause this. Test and enxure that the pH is below 7.8. High hardness (often in conjuction with high pH) can cause this, in which case a partial drain and refill with fresh water (with lower hardness) can help. Lastly, if the pool has not been drained in some time, high total dissolved solids (TDS) may be causing the foam. Again, this requires partial or full drain and refill with fresh water. Caution - make sure you know how much water you can drain out at a time in your pool in order to avoid damage to the pool (liner especially).