If there is very little water coming out the tube that drains into the sink (the acid tube), the unit may need cleaning because of mineral build-up on the electrodes. This usually does not become an issue for until at least 12-24 months of use. The safest way to clean the unit so as not to damage the electrodes is to recirculate WHITE VINEGAR through the unit using a small fish tank pump or small water-garden pump ($15 -- $40). 1. Unplug the Water Ionizer from the electrical outlet. Remove as much water from the Water Ionizer by blowing through the silver tube, inlet tube and acid tube. Also remove the filter and shake as much water from it as you can then replace it. The filter must be securely placed in the Water Ionizer for cleaning the ionizer in this method. 2. Prepare a container of WHITE VINEGAR for the pump. Attach the INLET hose from the Water Ionizer to the pump. Depending on the pump you purchase, this may require some minor modifications so that the hose will fit into the pump properly. Submerge the pump into the white vinegar. 3. Plug the small fish tank pump or small water-garden pump in to the electrical outlet. (A GFI safety plug should be used for this in order to protect against electrocution). 4. Place both the silver tube and acid water tube from the Water Ionizer into the white vinegar container so the entire system is recirculating. 5. At first, there may be very little flow through the silver tube. However, as long as the slightest amount of vinegar is flowing through the silver tube, the vinegar will eventually dissolve the calcium that is blocking the water from flowing out the tube. 6. Clean the Water Ionizer for 2-12 hours depending on how much calcium and other minerals have been deposited on the electrodes. 7. Reattach the Water Ionizer to your water source and flush the unit with water for 10-20 minutes to clean out the vinegar from the unit. 8. Begin using the Water Ionizer again. Calcium buildup on the electrodes causes the pH of the ionized water to drop because the source water is not coming in contact with the electrodes. Once your Water Ionizer is cleaned using this method, the pH of the ionized water will be higher because the water is now coming in direct contact with the cleaned electrodes. Tip: You can also remove the silver tube from the unit and submerge it completely in the WHITE VINEGAR overnight to remove much of the calcium build up. The reason for the calcium build up on the alkaline side of the Water Ionizer is because the high pH of the water causes the minerals in the water to precipitate out of the water and become displaced The Water Ionizer must be unplugged from its power source while cleaning the unit in this manner.