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RO/DI System FAQ's

RO/DI System Frequently Asked Questions


Is a reverse osmosis unit like a distiller?

• Both effectively reduce “dissolved solids” content of water, but the processes are quite different. RO filters water through a very tight semi-permeable membrane. A distiller is like a big tea kettle: it boils water, catches the steam, condenses it, and captures the resulting water. Most impurities are left behind in the boiling chamber. Both distillers and reverse osmosis systems rely heavily on carbon filtration for chemical removal. (Cheap distillers often have little or no carbon filtration and are, therefore, of limited effectiveness.)

Does a reverse osmosis unit waste a lot of water?

• Waste water is a byproduct of all RO systems. The non-powered (no electric pressure pump) Aquatic Life RO/DI Systems have a typical waste water rate of 4 to 5 gallons of waste to 1 gallon of filtered water. The Aquatic Life Powered RO/DI System (with pressure pump) produces less waste water with a typical waste rate of 1.5 gallons of waste to 1 gallon of filtered water.

• RO waste water may be collected and used for watering plants or outdoor irrigation. Some sort of holding tank and transfer system would need to be implemented. It is important to not impede the outflow of waste water from the RO/DI Systems.

What is TDS?

• Total Dissolved Solids or TDS is the combined content of all inorganic and organic substances contained in a liquid which are present in a molecular, ionized or micro-granular suspended form. The principal application of TDS is in the measure of water quality. 

Why is the TDS reading higher than zero for my filtered water?

• If a TDS reading is higher than desired, it could be that the membrane and cartridges need to be replaced. Water first passes through the sediment and carbon cartridges, then through the membrane and lastly through the mixed bed resin cartridge. The membrane removes the majority of TDS from the water and the resin cartridge removes the remaining. Replacement of the membrane and resin cartridges will usually minimize TDS.

• If water is allowed to bypass the cartridges or membranes, unfiltered water may be passing through the RO/DI System. Ensure that all cartridges are placed properly in the RO/DI System and that the seals are tight.

 Does the Aquatic Life RO/DI System remove Chlorine and Chloramines?

• Yes, the carbon cartridge removes chlorine and chloramines before the water comes in contact with the membrane. If the carbon is no longer active or water is bypassing the cartridge, the chlorinated water will damage the membrane and the water will not be filtered properly.

 How do I decide on the right RO/DI System?

 Consider these factors:

• How much water do I need to produce in a day? Aquatic Life offers models that produce either 60 or 100 gallons per day.

• How much waste water can I afford to have go down the drain? Waste water is a byproduct of RO systems. The non-powered (no electric pressure pump) Aquatic Life RO/DI Systems have a typical waste water rate of 4 to 5 gallons of waste to 1 gallon of filtered water. The Aquatic Life Powered RO/DI System (with pressure pump) produces less waste water with a typical waste rate of 1.5 gallons of waste to 1 gallon of filtered water.

How do I know when it’s time to change the filters?

• A TDS meter will be valuable in determine when a membrane and the cartridges should be changed.  A rule of thumb is change the sediment and carbon cartridges every six month. We sell HM Digital TDS Meters on Aquatic

How much water should I run through the unit to flush the membrane?

• Membranes are shipped with a preservative and need to be flushed prior to use. With a new membrane installed, allow 30 gallons of clean water to be produced prior to using the water for keeping aquariums.

Do micron sediment and carbon pre-filters remove TDS?

• The pre-filters (sediment and carbon) do not normally remove TDS (Total Dissolved Solids). The sediment and carbon cartridges are there for the removal of particulate and chemical matter such as rust, sand and chlorine.

• The RO process by itself cannot remove all of the TDS, but passing the water through a DI (mixed bed resin) cartridge after going through the membrane removes any remaining TDS. The DI media lifespan depends on what the TDS feeding it is like. This is why the RO process is recommended before a DI filter.

• The DI (or Mixed Bed Resin) cartridge is made with anion and cation resins for ion removal.

Can I connect the RO/DI System to the hot water line?

• NOT recommended - the elements of a membrane cannot withstand temperatures above 113 degrees Fahrenheit (45 Celsius). Most hot water lines operate above this temperature and should not be connected to a RO/DI System. The optimum water temperature for operating an RO/DI unit is 77 degrees Fahrenheit (25 Celsius).

Why does nothing happen when I plug-in my Powered RO/DI System?

• Check that there is power to the outlet.

• Check that the low voltage transformer is securely plugged in to the RO/DI System.

Why does the alarm keep sounding on my Powered RO/DI System?

• When an alarm sounds on the unit, an icon will flash on the display indicating the problem.  The user manual will identify the solution for each icon displayed. For example if the unit is not working and the “LACK” icon is displaying, this means the supply line is not sending water into the unit. Make sure your supply line is open and water is flowing to the unit.

How do I connect the internal tubing on my new RO/DI System?

• To minimize shipping damage, Aquatic Life ships RO/DI Systems with some of the tubing disconnected inside the unit housing. A step-by-step installation guide is included with each System.

My Deluxe RO/DI System is rated at 100 gallons per day. Why am I getting less?

Consider these factors:

• Dirty cartridges - As the system is used, TDS are accumulated and trapped in the Pre-filter and carbon block cartridges. Over time this can affect the pressure going into the unit. Keep up on the maintenance and replacement of these cartridges to avoid this issue.

• Water quality - The quality of the water coming in to the unit can affect the output. Some areas have a TDS as low as 100 while others can be as high as 600. Some water sources use chemicals such as chloramines while others do not. Utilizing a TDS meter to determine the levels of your water is ideal.

• Water temperature - The optimal temperature to run the unit is at 77 degrees.  If the water coming in is less, then your flow rate will be affected.  You will lose approximately 1.5% production for every degree below 77.

• Water pressure - The ideal pressure going into the unit is 65 PSI. Take your line pressure and calculate the output. An example would be a line pressure of 55 PSI. In this example your output would be 55/65=0.85 so you would produce 15% less.

Can I use a pressure canister with an Aquatic Life RO/DI System?

• Yes, using a pressure canister is possible with all Aquatic Life RO/DI Systems.