I had a very similar problem that was due to the use of water-wetter and some brands of vinyl tubing. While it looked like bubbles and "fogged" up tubing, it turned out to be a coating of some sort on the inside of the tubing. The first brand of vinyl tubing I used did not do this. After I replaced it with another brand (from Home Depot) it clouded over almost immediatly and looked exactly like the picture you've taken. Eventually I removed that tubing (and a water block that I thought was leaking) and replaced it with Clearflex 60. This tubing has stayed clear and "bubble" free for several months.
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