Replacing coolant

[JohnTedd]

I've been running my first watercooling system for two years now without any issues. I am going to upgrade the graphics card (water cooled) so I may as well change the coolant at the same time. I'd appreciate some advice as to whether I need to flush out the existing coolant/debris before putting in new stuff?

I have a Zalman Reservator XT and I used their coolant (mixed with distilled water). It was blue then, but now it is pretty much clear. Other XT users have experienced blue deposits in their system so I am worried there may be some of this lurking within. So perhaps it would be a good idea to flush it, but if so what do I use? Is ordinary tap water OK? I live in West London and the water here is pretty hard. If not tap water, what do people recommend?

Any advice gratefully received

John

 

[JohnTedd]

You are right, there are a mix of metals. The Reserator XT is Aluminium, the CPU block is copper base and Aluminium cover and the GPU block is also Aluminium. Their fluid is for a mix of metals:

Anti-Corrosion Coolant (ZM-G300)
This coolant contains a high quality anti-corrosion agent for various materials including copper, aluminum, plastic, and other metals that prevents corrosion for long term operation.

- Materials : Propylene Glycol & Anti-Corrosion Agent
- Weight : 250ml
- Freezing Point : -9℃
- Exchange Cycle : 1 year

However I am planning on using Eco-Earth from Fluid XP+, which is Aluminium safe and non-conductive/corrosive + bio-degradable.

I like the idea of using hot water to flush the system. If there is any blue gunk hopefully that'll shift it.

Cheers
John