How Do I Connect My Undersink RO Storage Tank?

Understanding Your Undersink RO Storage Tank

Your reverse osmosis storage tank is an essential component of your water filtration system. It stores purified water under pressure, ensuring you have clean drinking water available on demand. Proper installation is crucial for optimal system performance and water quality.

Before you begin, gather the following items:

RO storage tank with valve
1/4" tubing (included with Crystal Quest Thunder systems)
Low-pressure tire gauge (0-30 PSI range recommended)
Bicycle pump or air compressor
Teflon tape (if needed for threaded connections)

Connecting the Tank Valve to Your System

The tank valve serves as the connection point between your storage tank and the RO system. Follow these steps for a secure connection:

Locate the tank valve: Your storage tank comes with a valve pre-installed on top. This valve typically has a 1/4" threaded or quick-connect fitting.
Inspect the valve: Before connecting, ensure the valve is in the open position and free from any debris or damage.
Connect the tank tee fitting: If your system includes a tank tee, attach it to the tank valve. Apply Teflon tape to threaded connections to prevent leaks.
Tighten securely: Hand-tighten the connection, then use a wrench to give it an additional quarter turn. Avoid over-tightening, which can damage the fitting.

Quick-Connect vs. Threaded Fittings

Modern Crystal Quest systems use quick-connect fittings for ease of installation. If your tank has a quick-connect fitting:

Simply push the tubing into the fitting until it stops
Give the tubing a gentle tug to ensure it's secure
No tools or tape required

For any threaded fittings, always wrap the threads with 2-3 layers of Teflon tape in a clockwise direction before connecting.

Installing the Tubing

Proper tubing installation ensures efficient water flow between your RO system and storage tank. Here's how to do it correctly:

Cut the tubing: Measure the distance between your tank and the RO system's tank connection port. Cut the tubing squarely using a sharp utility knife or tubing cutter.
Inspect the tubing ends: Ensure the cut is clean and the tubing isn't kinked, bent, or damaged.
Connect to the tank: Insert one end of the tubing into the tank valve or tee fitting. Push firmly until the tubing is fully seated.
Connect to the RO system: Route the tubing to your RO system's tank port (often marked "TANK"). Insert the tubing into the fitting.
Check for kinks: Ensure the tubing runs smoothly without any sharp bends or kinks that could restrict water flow.

Tubing Best Practices

Leave a small amount of slack in the tubing to allow for movement
Avoid running tubing near heat sources or in direct sunlight
Use tubing clips to secure the line and prevent accidental disconnection
Keep tubing away from sharp edges that could cause damage over time

Checking Tank Air Pressure Before Use

This step is critical and often overlooked. Your RO storage tank uses air pressure to push water out when you open the faucet. The tank must be checked and adjusted before filling with water.

Why Air Pressure Matters

RO storage tanks contain a bladder that separates the air chamber from the water chamber. Incorrect air pressure can result in:

Reduced water storage capacity
Weak water flow at the faucet
Premature tank failure
System cycling issues

How to Check and Adjust Air Pressure

Ensure the tank is empty: For new tanks, this is already the case. For existing tanks, close the tank valve and open the RO faucet to drain the tank completely.
Locate the air valve: On the bottom or side of the tank, you'll find a valve that is similar to a bicycle tire valve.
Check the pressure: Using a low-pressure tire gauge (0-30 PSI), press it firmly onto the valve and read the pressure.
Adjust if necessary: The ideal pressure for most RO tanks is 7-8 PSI when empty. Use a bicycle pump or air compressor to add air if the pressure is low. Press the valve core briefly to release air if pressure is too high.

Important: Never check or adjust air pressure when the tank is full of water, as this will give you an inaccurate reading and could damage the bladder.

Tank Placement Considerations

Where you place your RO storage tank affects both system performance and your convenience. Consider these factors when choosing a location:

Ideal Placement Guidelines

Near the RO system: Shorter tubing runs mean better water pressure and fewer potential leak points.
Under the sink: Most residential installations place the tank in the cabinet beneath the kitchen sink for easy access and concealment.
On a flat, stable surface: The tank should sit upright on a level surface to function properly.
Away from heat sources: Keep the tank away from heating vents and appliances that generate heat.
Protected from freezing: Never install the tank where temperatures may drop below freezing, as this can damage the bladder and fittings.

Space Requirements

Standard residential RO tanks are 11 inches in diameter and 15 inches tall. Ensure you have adequate clearance for:

The tank itself plus 2-3 inches on all sides for air circulation
Access to the tank valve for future maintenance
Access to the air pressure valve at the bottom

Remote Tank Placement

If under-sink space is limited, you may place the tank in an adjacent cabinet or nearby location. Keep these points in mind:

Use the shortest tubing run possible
Avoid running tubing through walls unless absolutely necessary
Ensure the remote location is accessible for maintenance
Consider using a larger diameter tubing for longer runs to maintain pressure
Consider using a pump to boost pressure if too low

Final Steps and Testing

Once your tank is connected and properly positioned, complete these final steps:

Double-check all connections: Verify that all fittings are secure and tubing is properly seated.
Open the tank valve: Turn the valve counterclockwise to open it fully.
Turn on the water supply: Allow the system to begin filling the tank.
Check for leaks: Inspect all connections carefully for any signs of dripping or moisture.
Allow the tank to fill: This typically takes 1-2 hours depending on your water pressure and membrane capacity, all Crystal Quest undersink systems use 100 GPD membranes.
Flush the system: Once full, drain the first tank of water to flush out any carbon fines or residue from the filters.

Congratulations! Your RO storage tank is now properly installed and ready to provide you with clean, purified water. If you have any questions or encounter issues during installation, our Crystal Quest support team is here to help.

Need Additional Assistance?

If you need further guidance or have questions about your specific RO system, please contact our customer support team. We're committed to ensuring you get the most out of your Crystal Quest water treatment system.