SteriPEN® Defender is intended for use, and is most effective, in clear water. However, SteriPEN® purifiers have been shown to reduce microbial contamination in turbid water. If clear water is not available, first try to filter the water to clarify it - use a SteriPEN Pre-Filter, FitsAll Filter, bandana, clean cloth or coffee filter. If it is necessary to treat turbid, murky or cloudy water in an emergency situation, use SteriPEN® Defender as follows:
• To treat 32 oz. (1 L) of turbid water, use two 32 oz.- treatments. To accomplish this, push the operating button one time and complete the first treat-ment. Remove unit from water, wipe or shake water off sensors. Then push the button one time again and complete the second treatment.
• To treat up to 16 oz. (0.5 L) of turbid water, use a single 32 oz. dose. To accomplish this, push the operating button once and complete the treatment.
Turbidity is a measure of water clarity as affected by the presence of suspended solids. As turbidity increases, the suspended solids and murkiness of the water also increase. It is difficult to communicate a particular level of turbidity with just a written description.
Accordingly, please take into account the following when considering the use of SteriPEN® purifiers in water that is not clear: Laboratory testing has shown that a SteriPEN® purifier is effective in water with a turbidity of not less than 30 ntu (Nephelometric Turbidity Units) as described in the US EPA Guide Standard and Protocol for Testing Microbiological Water Purifiers, section 3.3.4. SteriPEN® has been successfully tested in water with a turbidity measurement of 33 ntu.
If viewing 33ntu water in a clear 1 liter bottle, one might characterize the water as follows: As cloudy as weak lemonade, Much closer to clear than opaque, Obviously not clear, Obviously cloudy, Objects viewed through the water are visible but blurry.