Water cooling: Is there a way to make the water's flow visible in transparent pipes?

[LMF5000]

As you are probably all aware, once you get all the air bubbles out of a water cooled system, the pipes will fill completely with fluid. This way, even if you have transparent pipes, you won't be able to see the water flowing through the pipes - they'll just appear a solid colour.

Is there something that can be added to the water to make the water flow visible just by looking at the pipes? Maybe something commercially available for this purpose?

If not, then what could safely be added for this purpose? One low-tech idea may be to use glitter or some other small solid particles in suspension, but I'd like to hear some ideas for chemicals that can be mixed into the water that make flow lines visible. I think concentrated automotive antifreeze changes colour slightly where it flows, so maybe areas of turbulence would be visible if this is used?

Another idea is maybe to add to the water a chemical that changes colour with temperature (same stuff they use for sticker thermometers) - that way maybe you can see some nice thermal profiles of the flow inside the water block if they have clear covers.

P.S. If you're wondering what the point of this would be, well, two somewhat good reasons:

1. Most water-cooled setups have windowed cases and transparent pipes. If you can visualise the flow you'd be able to tell at a glance if the pump has failed or some other flow problem has occured

2. I for one think it'd be cool to see the water going around in the cooling loop every time I look into the case

 

[Rubycon]

If you need visual confirmation of flow that is best served with an indicator mounted inline such as this one:

http://www.performance-pcs.com/catalog/index.php?main_page=product_info&products_id=33543

There are electrical (reed switch principle as well as photoelectric) ones that produce a pulse which can be converted to flow rate for monitoring and alarm/shutdown roles as well.

NEVER place particulates or any of the so-called "boutique" materials in your coolant. These WILL cause problems with pumps, clogging and reduce cooling efficiency and cause maintenance cycles to go through the roof!

 

[greenhawk]

as Rubycon mentioned, using a flow meter is best. Adding liquids will spread with time and you will be back where you started. Using glitter or something similar can result in it bulding up in bad places and effecting cooling.

Temp reactive ones might help by unless you are looking at it, it will not help with flow detection (assuming you getone that reacts in the temperature range you will be working in).

 

[BrightCandle]

You can check pump failure by plugging it into a fan header. Simply set the machine to shutdown if the fan is ever 0 and you have a fail safe if the pump fails.

 

[velis]

You can also use this:
http://www.ekwaterblocks.com/shop/reservoirs-and-acc/reservoirs/ek-bay-spin-reservoir-plexi.html
Most definitely noticeable (watch the embedded movie). Also doubles as a reservoir.

A bit expensive for my taste though. I'm building my own res from plexiglass right now. I intend to place the input pipe so that the water will flow right through the front visible part. A cheap solution, but an effective one nonetheless I think.

 

[Subyman]

I can tell by a slight bubbling in my reservoir.