i've used Primochills for my bro's WC'd system...

it foamed at start... but then i was a moron and had the res tilted so that the air got syphoned into the loop... but after a while, say, bout 24 hrs of running the loop, the foam dissappeared.

it foamed more when i used the newer product... the utopia line... the previous line, it did not foam as much... but the concentration of dyestuff was not enough to achieve the "looks"