It is an unfortunate truth that a large percentage of aquarium hobbyists must adjust their tap water to allow them to set a specific pH level or to remove unwanted elements (Nitrate, Phosphate, Silicates, Copper) from the water. Unless you want to lug around 1 gallon jugs of distilled water from the store, you have two in-house options. The easiest to use is a standard de-ion resin column like the Tap Water Filter. This is designed to allow the tap water to pass through the resin at a flow rate of approximately 10 GPH. The advantages to the de-ion resin system include a fairly fast production rate, no waste water and nearly all minerals in the water are removed. The disadvantage is the fact that the resin can become exhausted after rather small volumes of product water, 40-60 gallons. This makes it much more expensive per gallon versus the production cost of using a reverse osmosis unit.
A Reverse Osmosis unit is usually either a 3 stage or 4 stage filtration system. The 3 stage units will have a first stage Sediment Prefilter to eliminate particulates and bacteria from the water. The second stage is a Carbon cartridge (either a “block” or granulated) to remove some organics and trace elements, but more importantly, the chlorine from the water. Chlorine can damage the most commonly used type of Reverse Osmosis membrane used for aquarium applications, a Thin Film Compose (TFC) membrane. This membrane is the third stage of the RO unit and under pressure will eliminate 95-99% of all minerals in the water. This strips the water of all hardness and allows the freshwater hobbyist to adjust the pH to the wanted level with buffer solutions. Unfortunately for the marine hobbyist, elements that can get through the RO membrane include Phosphate, Nitrate and Silicate, three elements that can lead to nuisance algae. To eliminate these elements, you need a 4 Stage RO where the RO product water passes through a final de-ion cartridge. The advantage to doing it this way is to greatly increase the useful life of the de-ion resin. Disadvantages to using a RO unit include slower production rates, 20-100 Gallons Per Day, and waste water production can be 2-6 gallons for every 1 gallon of product water produced.
The Aquatic Life RO Buddie is a compact 3 stage RO unit designed as an economy model that will not take up too much space. This is a great RO unit for the freshwater hobbyist, or the marine hobbyist who does not have NO3 or PO4 in their tap water. While the unit includes a Faucet adapter to screw onto most faucets or utility sinks, you do need to purchase the ¼” JACO rigid tubing separately for the intake, waste water and product water lines. This unit includes brackets to attach the Sediment and Carbon cartridges to either side of the Membrane housing, and option wall bracket to hold the Membrane housing in place. Unlike RO units with screw off cartridge chambers, the Sediment and Carbon cartridges are all one piece. Plan on replacing them after producing about 700-1000 gallons of RO water. The RO Membrane can be rated either as a 50 or 100 Gallon Per Day membrane, with actual production between 70-95% of that total. This is dependent on your water pressure (60 to 100 PSI) and the temperature of the source water. If you need to also remove PO4 or NO3 from the source water, you can use an Add-On Deion chamber as a final stage to completely eliminate minerals in the water. The membrane should be good for 2-3 years under normal aquarium maintenance schedules. If you use the RO unit just every 2 weeks or so, it is best to remove the membrane from the membrane housing and store the membrane in a little bit of RO water in a plastic bag in the refrigerator. When you first restart the RO unit it is best to rinse out the water from the cartridges for 2 to 3 minutes before you start to collect any product water.