Paul,
I think it says that on the bottle. On the US website it says:
"using our AUTO-MIX UNIT. Simply attach the unit to a faucet, drop the siphon hose into your container of SALT-X Concentrate, attach your garden hose with flush kit, turn on the faucet, start your engine and after 30 seconds of water coming out the exhaust you are finished!! "
I will check the instructions on the bottle and get back to you.
Rob