It seems like a legitimate product description.
More info:
http://www.tygon.com/Data/Element/No...00000000001701
PDF:
http://www.tygon.com/media/documents...imicrobial.pdf
I couldn't find any specific references to recirculating applications, but there is a mention of using black tubing, which is really where we should be first looking, IMO; clear tubing is over-rated.
The clouding comes from the mixture of coolant (even plain water) with the plasticizer, a leftover residue from manufacturing. A good scrubbing or flush can clear it up (search here for the pine-sol flush, by Airspirit).
Note that this is food grade tubing, and probably doesn't have plasticizer residue. It's normally used in food dispensing.