Review - The API Tap Water Purifier
The Tap Water Purifier from Aquarium Pharmaceuticals Inc. (API) is a deioniser column consisting of
an ion-exchange resin and an activated carbon component. The kit includes one column with all necessary
fittings, plus a bottle of 'electro-right' and pH-adjust for restoring the necessary minerals and adjusting
the pH to the required level. It retails for about £50 in the UK, with replacement cartridges costing around
The column will remove all minerals including heavy metals, algae-promoting nutrients such as phosphate and
silicate, pesticides and organic pollutants, chlorine and chloramine and others. The column is easy to use
and can be quickly connected and disconnected from the tap. It produces 10 gallons of pure water per hour.
Unlike reverse osmosis (RO) units, there is no waste water. API say the unit should produce between 50-150
US gallons of pure water per cartridge, depending on the mineral content of the water.
Unfortunately, I was only able to obtain around 16 imperial gallons (20 USg/72 litres) before
each cartridge was exhausted. At a cartridge cost of £20 in the UK, this equated to more than £1 per gallon,
making it an uneconomical solution. My water is quite hard (GH 14) and often contains up to 60 ppm
of nitrates. If your water is quite hard and contains higher levels of impurities such as nitrates,
you may get very little water per cartridge.
I would therefore only recommend this product in the following situations:
- You only need a small amount of pure water and do not want a permanently connected RO unit.
- You have fairly soft water of a reasonable quality, and so will get a higher return per cartridge
(but in that case is a deioniser really worth it for most tropicals?).
- You want to further purify water from a basic RO unit, e.g. for a Reef tank.
Rob Smith also found that very little pure water was produced per cartridge from his hard tap water -
only around 12 gallons! Rob also found the electro-right and pH adjuster supplied did not give the hardness
and pH values stated.
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