RO filters

[caughtaniner]

RO filters, what are they, and do i NEED one? if i do, what kind shold i look into getting?

[hng]

RO = reverse osmosis. Reverse osmosis forces water through a semipermeable membrane with tiny holes that allow only water molecules to pass through but not larger molecules such as metals and phosphate. This is usually followed up with a deionizing filter that removes the small number of impurities that passed through the membrane. This produces what we call "RO/DI" water which is pretty close to pure water. It is important to use this because reef tanks are very sensitive to impurities, we are always striving to remove as much waste as possible. Unfortunately, tap water usually contains a ton of impurities (like nitrate, chlorine, phosphate, metals) that will adversely affect our tanks.

[caughtaniner]

what about uv filtration is this "the same" or is this somthing differant?

[hng]

UV = ultraviolet. UV filtration passes water through a chamber where it is exposed to UV radiation which alters the DNA of bacteria, algae, and parasites. This either kills or inhibits the reproduction of these undesirable things. So a UV filter helps to maintain the health of the tank but it won't kill all undesirable organisms. To work properly, the water has to move through the chamber slow enough for the UV bulb to adequately irradiate the water, but enough water has to pass through the filter that all of the water volume is treated - so in most cases, a UV filter that is worth anything has to be pretty big and unfortunately, expensive.