Corsair HydroX & EVGA GPU custom loop issues. Copper oxidation?

[Randomed]

Background:

1 year old build with custom loop cooling using all Corsair Hydro X parts (Radiators, Pump, CPU block, tubing, clear XL8 coolant) and an EVGA 3080 Ultra Hydro Copper GPU.

 

Issue:

I noticed some buildup in the tubing coming off the CPU block and thought it may be bacterial overgrowth or plastic. After tearing it down for maintenance though, I am thinking it may be copper oxidation. In the CPU block and tubing, there is a thin and flakey blue/green film. The tubing itself also has brown discoloration in other parts of the loop that don’t have blue/green build-up.

When I did my initial research, I thought this wouldn’t be an issue since all of the parts are either copper or nickel plated copper. XL8 also has an anti-corrosive in it.

 

Other notes:

I did have a small (but consistent) air pocket in the top of the CPU block due to its orientation. Should be fixed now after rotating the block.

On the worst tubes, some of the paint on the compression fittings was starting to flake off and expose what looks like copper underneath.

I replaced the worst tubing and I am currently flushing the system with distilled water and Primochill System Reboot.

 

So, a few questions:

What is this and why is it happening?

What can I do now to prevent or minimize the damage?

[Latharion]

This looks like algae growth or bacterial growth.  Did you flush your radiators before the final fill?  The radiators should be flushed with distiller water or distiller water and a flush additive, or a solution of distiller water and vinegar, and then flushe3d with straight distilled water.  This will remove oxidized flux and other sediment that may still  be lurking within the radiators.  The tubing should likewise be flushed.  The blocks probably do not need to be flushed though it would do no harm to do that.

 

One thing that can be done to help prevent future growth issues is to run the pump at a higher RPM, and vary the RPM occasionally.  Algae and bacteria both prefer stagnant flow so if there are areas that receive less flow or the flow is slower overall, it could cause some to show up.  Maybe also research if an anti-algal additive can be used with XL8.

[LeDoyen]

your tubes on the fist pic look very kinked. if they are, you'll have slow flow which will make things even worse.

air bubbles shouldn't linger in the CPU block either if you have enough flow. they get pushed out eventually. it can take a couple of days to get rid of all but it won't stay a whole year.

[Randomed]

The color of the material is what had me concerned about copper oxidation or corrossion. I should also mention, whatever it is, it was more evenly distributed around the inside of the tubing originally. In the first picture those clear spots in the tube are where I had pinched the line and the blue/green material coating the tube flaked off and bunched up at the radiator. 

 

When I built it, I flushed/shook the radiators with distilled water and then flushed the whole loop with distilled before filling it with XL8. Nothing else though.

 

The tubing does have a slight twist coming off the CPU and the radiator in the background. It looks worse in the picture than it is, but I will probably replace them if I have enough extra tubing. Flow seems to be okay, but I am just eyeballing it. 

 

I have been using the HydroX Pump default in ICUE and it seems to be running around 2000 RPM most of the time. What RPM are you running at usually?

 

 

Edited June 25, 2023 by Randomed

[Randomed]

This is what the whole loop looked like in better days.

[Latharion]

I run my pump at full speed currently, but I do cycle it to about 60% now and then.  I used to run it at 55% but my loop started to develop growth issues so now I run it at full speed and have noticed no growth issues.

 

Your loop looks good though.  Mine is very similar to your setup with the main difference being mine has an extra 360 rad in the loop.  I also used soft tubing (as you have) instead of rigid, and I've found that it works great.

[LeDoyen]

your loop should not develop any kind of gunking or growth, no matter the flow. If you have anything happening except cooling components, drain, flush, and put another better coolant.

low quality soft tubing can also leach plasticizer in the loop but it doesn't seem to be it, it's solid here. 

Since it seems to start at the outlet of the GPU, it could be bacterial, or colant breakdown, since it seems to happen where the water is the warmest. But again, with a good coolant, nothing should happen, at all.

The HydroX shows pump speed going up to 4800 RPM or 2400 when at full speed ? sometimes it halves the reading to show the real RPM value, sometimes not.

If the pump maxes out at 4800, then 2000 isn't very fast. Usually with a D5 pump and a loop like this, >60% PWM is a good starting point. lower and you may start to see some temperature increase depending on your waterblocks. High flow doesn't make cooling better, but too low can certainly make it worse 😉

Regardless, you're good for a complete flush of the loop there. I imagine the top radiator may have channels starting to block because of all that material that flew up. 

It's probably toothbrush time for the waterblocks too.

[c-attack]

On 6/25/2023 at 6:37 AM, LeDoyen said:

It's probably toothbrush time for the waterblocks too.

Afraid this is going to be true. If you put it back together and don’t get all this out, it simply collects back in the gpu and gpu cooling fan channels, blocks them up, and kills your cooling performance, and then you get to do this break down and clean again. You may have to do the inside of some of the fittings too. There’s a lot of stuff in there. The “chemical rinse” is not going to get it all out and do be extra careful when loading it all back in. 
 

It certainly is a fantastic shade of green, but I think bio growth is the more likely. In order to get down to the copper, the nickel plating would need to come off first and even then, there just too much of it. Some type of metal erosion would look like a streak and not such a thick build up. 
 

2000 rpm should be plenty at idle and for a lot of people all the time. It should not leave stagnant sections. However, as suggested above the continued presence of that air pocket and all this yuck suggests the loop flow may have been restricted at some point really killing your flow rate. Even if the bottle of XL8 was an improper mixture, it would take something more to get this kind of result. Regardless, I’ll understand if you choose a different coolant next time. 

Edited June 26, 2023 by c-attack