The 3% hydrogen peroxide samples continue to look pristine, with no signs of filament discoloration since we began testing on Feb 3rd (7.5 weeks) at 99% RH. We are declaring peroxide the clear winner in this testing and will be recommending going forward. 
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No changes, but we are amazed the filament in the tap water containing a copper penny is still total free of discoloration after 18 days. 

Allowed filament is soak in white vinegar over night on March 5th, rinsed thoroughly with water, and inserted into reservoir. There is now water flow into the loop end of the filament, but it is noticeably less than through a new filament. So, soaking in partially effective at restoring dried out filaments. 

We're sure most of our customers would be interested in extending the life of their filaments, although some simply replace them on a routine schedule. We would like to understand why a filament after being wetted and allowed to dry out, seems to have little water transmission or  stop working altogether. One observation is that the dried out loop tends to have some discoloration, which might point to some form of microorganism grew there - and possibly died there - after the water stopped reaching that area. This organism or its residue may reduce the water transmission to the point the filament can't keep up with the demand and simply dries out. Another possibility is that there is mineral deposit forming in the area, also reducing the water transmission to the point the filament can't keep up with the demand and simply dries out. 

In the Mold and Mildew Test initiated in early Feb 2020, we're not seeing any discoloration of the samples containing 3% hydrogen peroxide, leading us to believe the discoloration is mostly from micro organisms. We would not expect peroxide would control mineral deposits  - or that distilled water would contain much in the way of minerals. 

So, we've allowed a filament to dry out, and confirmed there is no water transmission in the discolored portion of the filament loop. We just began soaking in distilled white vinegar, which consists of 5 to 8% acetic acid (CH3COOH), water and trace amounts of other chemicals, and know to kill bacteria and viruses. We'll observe whether the discoloration is reduced or eliminated, and then re-test the filament.  

The discoloration on the tap water only and distilled water only has not worsened. And the addition of 3% hydrogen peroxide to these samples recently has not reversed the discoloration. The rubbing alcohol samples have about the sample discoloration as reported previously - not noticeably worse. The original distilled water samples with 3% hydrogen peroxide added still look as clean as at beginning of testing on Feb 3rd. The tap water sample containing the copper penny shows no change at Day 4. 

We recently switched the HumiForm Cigar Humidifier filament tubing from painted PVC to copper. In doing so, we learned about copper properties in reducing micro-organisms. There appears to be a long history of using copper as a way of reducing mold growth for containers holding water, although the mechanism doesn't seem to be well understood. For curiosity, I've added a new container of tap water with a filament, and dropped a penny inside today. Will begin monitoring and reporting along with previous containers and filaments.