Not exposing coolant to light seems to work
 

I've just flushed a system that's been running 24x7 for the last two years.
Innovatek HPPS pump + Innovatek push-on res (ABS version)
Swiftech 5002 block (anodized aluminum back)
mercury montego heater core
opaque soft silicone tubing.
10% solution of distilled water and Valvoline Racing Coolant

Everything looked good. A very thin layer of grey or white colored deposit inside the res. Didn't seem to be inside the block or inside the small length of hose I split open to examine - maybe just built up where the coolant slows down.
Pump internals looked pretty much new
Nylon barbs on the 5002 has soaked up a little of the VRC pink dye

Buttoned back up, refilled with distilled water and 5% VRC (I'll know in another two years whether the 10% was more than enough...)

Note - I'd given the owner a couple of bottles of DW/VRC at 10% mix. (silicone hoses lose water a bit faster than vinyl, so there's a need for bi-monthly top-up). If the walls of the silicone tubing are working as some sort of osmotic filter (i.e. water goes out, VRC stays) it's possible that the concentration has been going up as he refills). He'd gone through about a pint (if we both remember correctly how much I gave him).

Oh - and the piece of foam I'd put under the pump/res combo to damp any pump vibrations before they got to the case had gone almost completely flat. :)

[edit] changed Innovatek push-on rad (ABS version) to Innovatek push-on res(ABS version) ... duh![/edit]

Re: Not exposing coolant to light seems to work
 

It makes a case for black tubing... ;)

Re: Not exposing coolant to light seems to work
 

Was there any corrosion in the 5002? Or did the VRC take care of it?

Re: Not exposing coolant to light seems to work
 

It looked slightly tarnished (not bright copper color any more).
I don't know if this was the VRC or just not having any non-copper metal exposed to the coolant (the Swiftech alu block-top is hard anodized, which, so long as it is unbreached, does a very effective job of chemicaly isolating the alu from the loop). AFAIK, copper is unlike alu in that, if it's in a loop alone (no mixed metals) it doesn't really need anti-corrosion...

Re: Not exposing coolant to light seems to work
 

I'm running black tubing and it's doing wonders for keeping the creepy crawlies out of my system! (I'm running no additives, stupid living on campus so i can't go to the auto store to buy antifreeze...)

Re: Not exposing coolant to light seems to work
 

Any links for black tubing (1/2") in the UK? :)

Re: Not exposing coolant to light seems to work
 

how bout a link if possible for the tubing? I been thinking of getting some but couldnt find any.

Re: Not exposing coolant to light seems to work
 

Search for TYGON UV resistant tubing R-3400
Link: ="http://www.usplastic.com

Re: Not exposing coolant to light seems to work
 

That's interesting news. I've always wanted to try black Tygon anyway. I wouldn't run without at least some form of antibiotic though. Life will find a way if at all possible.

Re: Not exposing coolant to light seems to work
 

I can prove that! I just found the first signs of stuff in my system. I really need money to buy some antibiotic/antifreeze...

Re: Not exposing coolant to light seems to work
 

Hydrx is cheap. I've seen if for as little as $4/bottle. Can you describe what you're seeing?

Re: Not exposing coolant to light seems to work
 

you would need to do a more straight comparison to convince me, like filling 2 systems in the same room with identical coolant and just have the difference be the tubing, because UV radiation in general kills bacteria so I could see a case in direct sunlight fairing much better than the cool damp places moldies seem to like soo much.

Re: Not exposing coolant to light seems to work
 

Hydrx @ $1.99 http://www.svc.com/swhyexduco.html

Re: Not exposing coolant to light seems to work
 

The amount of UV required to kill bacteria is actually quite specific. If you mean case light UV CCFL's, they don't even come close. A UV lamp powerful enough to sterilize would be hard on the eyes too.

Re: Not exposing coolant to light seems to work
 

yah but what about a few hours of direct sunlight if say a windowed case or resevoir was right in the sun, I feel that would be more than enough to kill most common bacteria. I'm just not convinced that by taking OUT the uv radiation and light would kill the bacteria, it could be something else like the property of the tubes or water but this just seems really ancedotal to me

Re: Not exposing coolant to light seems to work
 

maybe this is a stupid question.

But if the bacteria are photosynithising then black tube would work right. The bacteria have to be living off something?

Re: Not exposing coolant to light seems to work
 

The type of UV radiation affects how well it kills bacteria. To kill bacteria you need UVC radiaton, with 264nm being the most effective frequency. The sun emits plenty of this, but it's all absorbed by ozone and oxygen in the upper atmosphere. Putting a windowed case in direct sunlight won't kill anything, it'll merely give it lots of light to grow with.

Also, CCFLs are generally "blacklight" or UVA frequencies and thus don't harm bacteria (or people).

As for why taking out the light kills bacteria - light is the energy source for it. Without light it has no source of energy and dies.