UPDATE : PrimoChill PrimoFlex Advanced LRT Working, Tygon E1000 Working. "DEHP" free tubing is recommended for use with Mayhems pastel coolants.
What is DEHP
First off the EU has been pushing to ban "DEHP" (since 2011) in medical equipment for the last few years and finally manufacturers are now taking up the proposals. The ban if it goes though will be enforced with in the next few years so if manufactures don't move over they could find them facing some severe penalties if and only if the proposals go though.
DEHP is highly lipophilic (fat soluble). When used in PVC plastic, DEHP is loosely chemically bonded to the plastic and readily leaches into blood or other lipid-containing solutions in contact with the plastic. In water Cooling terms "DEHP" is what has been causing Gumming up of water cooling blocks for years and people have been wrongly blaming the coolants because of this. When "DEHP" reaches temps of around 38c and above the leaching process is exasperated in our findings and this is when problems start to occur. Also the use of some biocides also do not help and cause the "DEHP" to leach at a faster rate.
The reason why some people do not have a issue and some do is all down to the temperature of the liquid inside your system. The hotter your water is the more apparent the problem becomes. E,g If running a 2 x 120mm rad on a system that has a GPU and CPU block then the risk of "DEHP" leaching is higher than is running the same system on a 3 x 120mm rad with the same fan speeds and though put.
Some sources of information for you ->
DEHP - the penis shrinking chemical ->
http://articles.mercola.com/sites/articles...a-does-not.aspxWikipedia -
http://en.wikipedia.org/wiki/Bis(2-ethylhexyl)_phthalateDEHP Information centre -
http://www.dehp-facts.com/RAThere are many forms of tubing out there and "DEHP" is in a lot of them. Tubing that is "DEHP Free" is not a cheap as tubing that contains "DEHP" how ever would you rather spend a few pounds, euros or dollars more on some thing that is going to help keep your system clean and gum free. the choice is yours.
Primochill we salute you for leading the way .