Originally Posted by Marci
Find someone running a rig on Silver Antimicrobial. Get them to check for any sludge or buildup within blocks (obv needs to be someone who we can guarantee is running a "correct" coolant > additive ratio etc, pref someone running no mixed metals and plain distilled, who has flushed their hardware prior to fitting etc). Monitor their rig over a period of months to see if sludge appears...
And I'm not saying it's a microbial problem... just a feature of that particular tubing...
It's not a fact, but it's prime suspect for the cause of sludge and deposits amongst a few folks.