The programme rather than the hardware.

Water pattern, temperature, light and scent vary across a cycle.

Identical nozzles can produce different experiences.

The sequence is the designed product.

Ask which programmes ship with the unit.

Ask who can change them afterwards.

It depends on who operates the facility.

Seasonal offerings need an editable controller.

A chain wanting consistency needs the opposite.

Editing rights should sit with one role.

Uncontrolled editing produces drift between sites.

Settle the policy before choosing the controller.

Stable pressure and a real flow rate.

A cascade pattern is the demanding case.

An inadequate supply shows immediately.

Peak demand rather than average sizes the pipework.

Drainage has to take the same peak.

Confirm both against the unit's data sheet.

The programme changes temperature quickly.

A conventional mixer cannot respond in time.

Tempered supplies arrive at the unit already blended.

The controller then selects between them.

This also guards against scalding.

It changes the plant room layout.

For guests who will not immerse, largely yes.

A short sharp cold pattern serves the same purpose.

There is no standing volume to treat.

No chiller runs between users.

The sensation is briefer and less intense.

Many facilities offer both for that reason.

It adds a consumable and a supply dependency.

Cartridges have to stay available for years.

Cost recurs for as long as the unit runs.

Guests notice its absence once it is introduced.

Some markets restrict permitted fragrances.

Confirm availability in the operating region first.

Nozzles, valves and the controller.

Scale blocks fine nozzles in hard water.

Descaling frequency follows water quality.

Solenoid valves are the usual wearing part.

Light sources are long-lived but not permanent.

Keep the programme configuration backed up.