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Green crystalline solid forming around rubber seals - what do?

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New Member
Mar 15, 2016
Haven't opened up this loop in over a year. A few of the fittings and end caps have some of this (copper sulfate/chloride?) precipitate on them but the CPU block is fine. GPU blocks are similar but have the pictured residue. It only seems to manifest against nickel surfaces rather than copper, although the nickel reservoir seems totally clean. No aluminium or other metals in the loop besides a small silver kill coil. Haven't yet washed out the radiators, gonna do that next. Have I got some low-scale galvanic corrosion going on? Photo:

Did you use a copper sulfate based biocide?
It appears to be just residue from that.
Green is usually the sign of growth or from colored tubing. Going to have to take apart the CPU block and clean and just rinse the heck out of the GPU, including your rads. Just give your loop a nice bath and let us know what you discover. Some images would be nice as well.
We all like pictures here! :D

Did you run any dyes in the loop? or just Distilled water?