Reverse Osmosis

Due to the poor quality of tap water in many areas the use of a reverse osmosis unit is becoming more important. This is especially important where sensitive species are concerned.

What is it?

Reverse osmosis is ultra fine mechanical filtration (1/10,000 of a micron). This ultra fine filtration is achieved by forcing water through a semi permeable membrane. This removes almost all contaminants and produces very pure water. This is a slow process as one part of pure water is produced for every five parts rejected.

Do I need a reverse osmosis unit?

Reverse osmosis units produce water of exceptional quality, they are most often used by keepers of marines and delicate freshwater fish. However, anyone who suffers from poor quality tap water will benefit from the use of an R.O. unit as they remove almost all nitrate, phosphate & many other pollutants as well as helping to reduce the pH. See table for full list of pollutants & percentages removed.

The Membrane

Most units are supplied with a thin film composite (TFC) membrane. This type of membrane is resistant to bacteria, but will be damaged by water containing Chlorine. Therefore all units fitted with a TFC membrane need a carbon pre-filter to remove the Chlorine. Some units are also fitted with sediment filters to prolong the life of the membrane. These pre-filters are best replaced every six months. If looked after well the membrane can last up to five years before

needing replacement. All membranes are rated in U.S. gallons at 77°F and 60 PSI water pressure. Therefore in average conditions in this country a 10 gallon per day membrane will produce a maximum of 8 imperial gallons of good water per 24 hours of continuous running. Purity on Tap R.O. units are fitted with an intermittent use kit this means they can be safely turned off safely for up to 48 hours If they are left off longer you risk shortening the life of the membrane.

How are they installed?

All reverse osmosis units rely on mains water pressure to force water through the membrane, this pressure must be at least 30 PSI. All Purity on Tap units are supplied with the appropriate fittings to connect them to the mains water supply. These fittings consist of a special tap that pierces & seals ½” copper tube. A pipe then connects this tap to the R.O. unit. Remember, also have a drain close by to dispose of the waste water.

Compound

Aluminium
Ammonium
Arsenic
Bacteria
Barium
Bicarbonate
Bromide
Cadmium
Calcium
Chloride
Chromium
Chromate
Copper
Cyanide
Fluoride
Hardness
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Nitrate
Phosphate
Potassium
Radioactivity
Selenium
Silicate
Silver
Sodium
Strontium
Sulfate
Sulfite
Thiosulfate
Zinc

% removed

96-98

80-90

93-95

99+

95-97

85-95

90-95

93-97

92-95

95-97

85-95

96-98

85-95

92-95

93-97

96-98

95-98

93-98

96-98

94-98

96-98

90-95

95-98

92-96

93-97

93-94

92-95

93-96

92-98

95-97

96-98

94-96

96-98

D&D 40GPD R.O. unit

D&D 40GPD R.O. unit £79.95

callers only.

Download PDF (100k) instructions for this Reverse Osmosis unit. Please note, the picture in the instructions does not match the product, but directions are accurate.

In addition to this the carbon pre-filter will remove pesticides & Chlorine.

For those who would like R.O. water but do not wish to purchase a R.O. unit we can supply R.O. water at 15 pence per litre. Please bring your own container.