What cleansing agent is explicitly mentioned for spa system flushing?

The correct choice regarding the cleansing agent specifically mentioned for spa system flushing is low sudsy soap. This option is important as spa systems require a cleansing agent that effectively removes build-up and contaminants without producing excessive foam, which can interfere with the flushing process. Low sudsy soap is designed to minimize suds, allowing for thorough cleaning of the spa system without causing complications in the plumbing and drainage systems.

Using dishwashing liquid, bleach, or regular hand soap might result in an overload of suds or undesirable chemical residues that could harm the system or leave behind unwanted residues. Therefore, low sudsy soap is specifically crafted to meet the needs of spa systems during flushing, ensuring effectiveness while maintaining system integrity.