Fri Aug 12, 2022 10:01 pm
About the moisture strip that we all relied on for years...
It's not as foolproof as was once believed. Turns out that it is common for larger volumes of incoming air to channel up through the central portion of the drying media, causing it to adsorb more moisture than the outer most area. The test strip can remain blue even though the central portion of media is getting moist due to more air volume (and its moisture load) passing through it. Some filter cartridge manufacturers are leaving the strip out because of the potential for it giving an inaccurate blue color reading.
A small moisture sensor device installed just downstream of the main filter tower gives a much more accurate estimate of the moisture content of the treated air. These cylindrical devices are typically about 3 to 4 inches long and about 1.5 inches in diameter, and have a thick clear view port. That port gives a view of the same type of moisture indicating paper, showing up as blue when the air is appropriately dry, and fading to tan or white when moisture is greater than desirable for diving use. Prices can vary but I see them anywhere from 50 to $70 range. They work well, and have the added advantage that you can check the air moisture content any time without opening up the filter tower and removing the cartridge for a view.
The older I get the better I was.