The Evolution Aqua de-ionisers purify tap water using a de-mineralising process called de-ionisation. Each filter contains special colour change mixed bed resin that removes harmful anions and cations from tap water. They remove 99.99% of all chemicals, mineralsand metals from tap water, purifying it to zero parts per million. Purified water is produced instantly with no waste water and is safe to use immediately once your desired temperature is achieved. Ideal for new tank set-up giving a “pure-base” for you to recreate the ideal environment for your hobby fish. Also ideal for partial water changes as pure water dilutes remaining contaminates more effectively than tap water. These filters remove calcium which means that heaters, hoods and light fittings do not become coated with hard water deposit. Maximum recommended flow rate 1 UK gallon per minute (1.2 US gallons or 4.5 litres). Our filters are 100% recyclable, please dispose of as a plastic item.