0 FC or Low FC - WaterGuru SENSE

Note:  Unlike pool store test strips that can vary in accuracy, the test pads that the WaterGuru SENSE uses, provide very accurate FC and pH chemical readings that are matched against the accuracy of the highly rated Taylor Test kit K1515A.  The Taylor Test kit K1515A is available from Amazon for about $35.  

If you are getting 0 FC or low FC readings in the App, check the following:

Water Flow in the Skimmer

• The Free Chlorine FC levels in the skimmer can read lower than the actual level of FC if there is not enough water flow in the skimmer.
• If you are using a mesh bag, remove the mesh bag
• The SENSE needs to have adequate water flow in the skimmer in order to provide accurate readings. Water that is stagnant in the skimmer will not provide good readings.
• Check if there is a sufficient water exchange in the lab unit by cleaning the filters on each side of the lab unit. Use warm water and mild detergent solution and rinse. Put drops of water on the L-shape opening and see if the water flows through. Do the same on the other side with the flat slots opening. 
• Schedule your daily water measurement at a time in which your pool water pump is running. At least 30 minutes to an hour after the pump has been turned on. 
• Note: If you perform a manual measurement "Measure Now" from the WaterGuru App, ensure that you do so only when the water pump is running.

Low CYA levels with sun exposure to the pool water

• Ultraviolet rays from the sun can reduce chlorine by up to 90 percent within two hours if CYA is not present.
• During the summer months the sun is directly overhead and will heat the water to higher temperatures than in Spring or Fall, reducing chlorine much faster.

High CYA levels

• It is important to check if Cyanuric Acid {CYA} levels are high in your pool. 
• High CYA levels require higher FC levels to have the same active Chlorine that prevents algae and bacteria from growing.  High FC levels can become impractical. High CYA levels should be lowered through water dilution.

Mineral Pool systems, Ozone, or UV Filters

• If you are using Mineral Pool systems, Ozone, or UV Filters with very low chlorine requirements for the pool, you may be receiving low FC alerts which are normal for your type of pool. 
• Please contact WaterGuru Customer Support. We can set a custom low FC target for your pool so you won't receive constant low FC alerts.

WaterGuru TEST

• We also recommend sending us a water sample (TEST Kit) which will provide you with a complete water analysis to check other factors including CYA that may consistently affect low FC reading.