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How to clean your loop without taking it apart?

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Jul 19, 2013
So I'm building a new system with a few old (but clean) parts where I'll be using destilled water (and nothing else) as coolant.

To extent the time between maintenence runs I have installed an in-line UV-sterilizer.

Galvanic corrosion may become an issue, but I'm prepared to take that chance 😬

I have used PrimoChills cleaning program in order to start out in the best possible way.

Rad Clean (rads only), System Reboot and SysPrep.

I have flushed with destilled water after each treatment.
Pump ran for 24 hours per flush.


With what I had hoped would be the final run (after 2x flush with destilled water) I powered up the UV-sterilizer...

After two hours the water looked like beer... (or urine)... Take your pick...

I would have uploaded a photo, but don't know how (on my phone).

Water had been cristal clear with ZERO color shift (for more than 24 hours) right up to the point where I fired up the sterilizer.

UV light does not turn destilled water into "beer" (unfortunately) 🍻

So I'm guessing that PrimoChills cleaning products does not play well with UV-sterilizers.

I THINK the SysPrep coated the inside of the loop with something in order to prevent galvanic corrosion - But that "something" and UV light is a bad combo.

So, how do I best clean out the system WITHOUT pulling it apart??

Thanks 👍
I'm not sure "just" getting the fluid out is enough...

I think the PrimoChill SysPrep coated the inside of the loop (as designed) and THAT coating is dissolving somewhat into the destilled water and reacting badly with the sterilizer.

I'm NOT saying PrimoChill made a bad product ☝️
I just happened to use it "out of spec"..

But I THINK I need the coating gone as well - even though that may actually open up for galvanic corrosion....

Do I use their "Reboot" to remove the coating, or...?
Vinegar will strip it. Then flush clean with distilled. That's all you need.