A shock (or oxidising) product removes dissolved organic matter and non-filterable waste from the water, including perspiration, urine and decomposing flies! - All best removed!.
Clarifiers 'polish' dull water by removing small suspended particles that filters ordinarily cannot capture. They work by coagulating the tiny particles into larger ones that can be trapped in the filters.
Scum absorbers are foam products that float on top of the hot tub water, soaking up surface oils and grease. They can help reduce foaming and make the water stay clearer for longer.
Foaming is caused by pollutants in the water. Common culprits are make-up, body lotion and hair gels Anti-foam is an additive that reduces the foam formation, but unfortunately it can also make the water look dull.