what type of water for reserator...distilled or de-ionised?

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malcky h
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what type of water for reserator...distilled or de-ionised?

Post by malcky h » Thu Oct 21, 2004 12:10 pm

hi folks,

as title what is to be used in the reserator, as i can find de-ionised water easily but havnt seen distilled water execpt from buying it online but i want it for tomorrow as thats when the reserator will be delivered.

cheers

TheDarkHacker
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Post by TheDarkHacker » Thu Oct 21, 2004 12:14 pm

distilled with 10% antifreeze

ferdb
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Post by ferdb » Fri Oct 22, 2004 4:17 pm

you should be able te get distilled at a supermarket or pharmacy. I got a gallon far about $1

Rusty075
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Post by Rusty075 » Fri Oct 22, 2004 5:59 pm

Distilled is best, but deionized will do. (Distilled is easily here in the US, it may not be in the UK)

Deionized water is just that...water that has been passed through a column or membrane to remove ions, it could still have lots of non-ionic organic matter in there.

Distilled water is boiled in a still, and then the condensate is collected, which removes both ionic and nonionic contaminants.

You should be adding an anti-corrosive/antimicrobial agent anyway, regardless of the water type.

DrJ
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Post by DrJ » Mon Oct 25, 2004 8:28 am

Actually I don't think it will make much of a difference which type of water you use. As long as hardness is removed (namely, Ca, Mg, Mn and Fe) I doubt you would see any difference, particularly once antifreeze, anti-bacterials and anti-corrosives are added.

FWIW, DI water is usually produced by membrane filtration; the exact composition of the final product depends on the particulars (pressures, whether it is an RO or nanofilter, and process configuration). Mix-bed ion exchange is terribly unattractive for this application, and is used only for polishing DI or distilled water.

Distilled water is not as clean as one might think -- a lot of organics are quite volatile and go overhead. Droplet entrainment also lessens purity.

Of course, I have an ultrapure water supply, so I would use that if I needed water for cooling applications...

DrJ

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Post by Rusty075 » Mon Oct 25, 2004 8:35 am

And there's also the fact that by the time you get the water from the jug and into the system, it's at least partially re-ionized anyway. Not to mention that DI would quickly pick up ions from the metals in the system as well.

DrJ is dead on: there's really little practical difference, go with whatever you can get.

DrJ
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Post by DrJ » Mon Oct 25, 2004 8:55 am

If you mean that you pick up a bit of carbon dioxide when you transfer it from container to the system, sure. Shouldn't make much difference.

I admit that I don't understand the obsession with water purity for this application. Get rid of hardness, and make sure that there are chelating agents to keep the metals soluble, perhaps some buffers to keep the pH in the right range and, most importantly, anti-bacterials to keep biofilms from forming. Bacteria, more than anything, will kill the heat transfer abilities of the system. Bacteria can, and do, grow just about everywhere. Particularly where they are not wanted.

DrJ

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Post by Rusty075 » Mon Oct 25, 2004 9:23 am

Actually I was thinking (but didn't type) about the fact that the Res isn't a sealed system...it's always open to the atmosphere, so the water will eventually saturate with gases (and who knows what else comes floating in)


I think even the corrosion and biological growth issues are often over-stated in WC'ing. I've never seen a real scientifically controlled experiment looking at the corrosion or biological issues specific to PC cooling loops. Lots of anecdotal results, but very little real science. "I filled my loop with mayonaise and it didn't corrode" does not count as science. :wink:

DrJ
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Post by DrJ » Mon Oct 25, 2004 10:36 am

Does the Reserator have a vent hole? Probably a good idea, and again, not a big deal as long as the coolant has decent basic properties and the coolant is replaced once in a while.

I'm not into water cooling on computers, but I suspect that your statement on scientifically-validated results in this area is correct. On the other hand, there is an enormous literature in water treatment that should not be ignored. And yes, many lives ago I used to design these things.

My point is similar to yours, that most of this obession seems to be misplaced. And most people overlook biology -- it is so much easier to deal with ions as a single figure of merit. That alone is not very helpful.

It may well be that the capacity of these systems is so large that even biofilms do not matter much. It would be pretty easy to measure, actually. Still, biofilms can have a large, and deleterious, effect on heat transfer coefficients. And once established, they are really, really hard to remove. Simply replacing the water or flushing for a while will not do it. Often shock chlorination will not remove them. One can resort to esoteric chemical means (which I have done to remove biofilms from the water distribution system of a subdivision of 120 homes), but that is not really an option for the average user.

So I'll go back to my original advice. Use water without hardness (but not softened -- too much salt). Either distilled or deionized is fine. I would suggest to pay attention to supressing biofilms and, to a lesser extent, corrosion. I'd think that automotive antifreeze would be a fine additive, as it has to deal with generally similar concerns and consequently has had a lot of science and engineering applied to it, and is readily available and inexpensive. Gotta be careful about disposal, though...

As a side note, please be aware that a lot of bottled waters (including DI and distilled) have quite a bacterial content. I worked with one of the leading bottled-water companies to get it out of their (contaminated) product. You should assume that it has bacteria that grow well in reasonably-pure water environments, including water-cooling systems.

DrJ

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Post by Rusty075 » Mon Oct 25, 2004 10:45 am

Yes, unlike nearly every other WC kit, the Res1 has a built-in vent hole in the top of the reservoir.

I'll default to your expertise here: Why is having a vent hole a good idea? (we had some debate as to why, but it went nowhere)

The consensus everywhere else in WC-land is that you want the system sealed tight-as-a-drum against the outside world.

DrJ
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Post by DrJ » Mon Oct 25, 2004 11:11 am

Having a vent hole would seem to make the unit much more convenient to use and maintain. You don't have to "burp" it (like you do a car system), you can remove the top while it is running to add or remove coolant as you like (to measure the conductivity, pH or bacterial load, for example) or measure the temperature. That depends on how the return line is designed, I guess, but this should be possible.

Closing it off makes all of this more difficult, and would lead to people ignore it.

Why is it claimed that a sealed system is better? Less oxygen and carbon dioxide in the system? I'd rather do that through chemistry (but that's my bag), and make the system easier to maintain.

DrJ

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Post by Rusty075 » Mon Oct 25, 2004 11:27 am

Preventing the introduction of biological contaminents is the reason usually given.

Even most "closed" systems have an access point for filling and bleeding, be it a T-line or a small reservoir.

The Res1 has the huge opening in the top for this purpose. My guess as the why Zalman included a little pin-hole in the lid is that it has more to do with breaking the "vacuum seal" that could occur under that big cover than anything else.


Thanks for letting me pick your mind! :lol:
Last edited by Rusty075 on Mon Oct 25, 2004 12:06 pm, edited 1 time in total.

DrJ
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Post by DrJ » Mon Oct 25, 2004 12:02 pm

>> Even most "closed" systems have an access point for filling and bleeding, be it a T-line or a small reservoir.

Only one? I would think that two (or a two-way valve) would be much more useful. As has been said, it is hard to push on a rope.

>> The Res1 has the huge opening in the top for this purpose. My guess as the why Zalman included a little pin-hole in the lid is that it has more to do with breaking the "vacuum seal" that could occur under
>> that big cover than anything else.

You're probably right. If this is an issue, why not cover it with, for example, plumbers' putty, or more properly, install a valve?

DrJ

DryFire
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Post by DryFire » Mon Oct 25, 2004 5:00 pm

i think sealing it may be more along the lines of preventing leaks?

we were talking about how they harvest organells through cell fractionation in biology today; would that not work in this case? (just a random thought)

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Post by DrJ » Mon Oct 25, 2004 5:18 pm

I don't quite understand your questions, so let me talk around them to see if I hit on something that makes sense.

In the researator, as I understand it (and bear in mind I've not seen one) you have a tube that is partially (half? two-thirds? a bit more?) filled with water. A pump draws it out of the bottom, through the computer and whatever heat exahngers you have therein, and it flows back into the pipe. Unless it is sprayed with some vigor towards the top, it is not going to leak out. Zalman adds a cap (with the pin hole) so that nothing falls in; the cap is not essential to its operation. The pin-hole is there simply to make the top easier to remove. I'm sure Rusty will correct me if I have a few of the details wrong.

Regarding cell separations, the issue for biofilms is getting the cells off the surface in the first place. These are growths that cling tenaciously to whatever they grow on; they have a lot more in them than just cells. If you are interested in details, look at the Montana State web site for Prof. Costerton. He runs a national center for excellence in the area.

Once you get the cells off the wall, you can do many different things to them to separate them, if you want. If they are dead, there's really no need, though they do provide a nice environment for more cells to attach to the dead flocs and thereby grow more cells. Easiest is simply to flush the system once in a while and replace with new.

But again, you really want to keep biofilms from growing in the first place. These are stubborn beasts.

DrJ

DryFire
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Post by DryFire » Tue Oct 26, 2004 7:09 pm

well as for the sealing part i was thinking more about systems inside a computer that is moved. no one wants water spilling in their case when they move it.

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Post by Mr_Smartepants » Tue Oct 26, 2004 8:42 pm

The hole in the top is there for two very good reasons.
First, the reserator acts as an expansion vessel as well as a radiator. In your car you have an expansion vessel (commonly refered to as an 'overflow tank'). When the coolant in your car gets hot, it expands, and 'overflows' into the expansion vessel. When the coolant cools (engine is off), the coolant contracts and the vacuum formed by that process pulls the coolant out of the expansion vessel and back into the closed loop system.
The second reason is to prevent pressure buildup during the heating phase. Water does not compress. When water gets hot, it expands. If the reserator were filled to the top with no air gap (and no hole), you would most likely burst a hose or blow off a hose connection from the pressure. Conversely, the vacuum formed during the contraction stage would prevent you from opening the top at all, or collapse a hose or two.
Zalman's website specifically states; do not fill reserator to the top.
The hole is just a safety precaution.

I doubt that liquid-loss through evaporation would be much through a pin-hole. Maybe a few ounces over 6 months use? To satisfy your curiosity, just take a plastic water/coke bottle and prick a pin-hole in the bottom/side/wherever. Then fill it to about an inch from the top and put the lid on. It wouldn't leak because even though the air inside could expand to take the place of the water, the atmospheric pressure outside would crush the bottle. The reserator has a bit more structural integrity then a coke bottle. :D

DrJ and Rusty are absolutely correct in the biology of it all. The little buggers would thrive in the nice warm water if no additive were introduced. On a budget, normal auto antifreeze is good but dedicated additives from PC watercooling companies are better because they've added cooling improvers (water-wetter), anti-biotics, and other great stuff.

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Post by Rusty075 » Tue Oct 26, 2004 9:39 pm

That was exactly what DrJ and I had already discussed. Without the hole the air trapped in the top of the Res would pressurize slightly under heating. That air pressure would likely equalize itself with the atmosphere through the o-ring over a prolonged time period, and would result in the "vacuum seal" I referred to once the system was cooled down.

It should be noted that most "closed loop" WC'ing systems make no provision at all for expansion of the coolant under heating. And with good reason: Even with the Res's 2.5L of water (which is 5x or more the amount of water in other systems) the expansion amounts to only about a tablespoon of water volume. The elasticity of the tubing will easily absorb that.

Actually, just did the math, and the expansion of the aluminum cylinder will just about equal the expansion of the water.


I don't think anyone worries about evaporation from the hole, its more an issue of the potential for things to go in the hole, not out. :lol:


Most of the stuff from the PC watercooling companies is nothing you can't buy from your local megamart.

uszobajnok
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Post by uszobajnok » Sat Nov 13, 2004 2:00 am

I put 2L destilled water, and 0.4L 70% alcohol in my Reserator. I think this is a good solution. The alcohol kills the bacterias, and I hope my system will not get rusty.

Daniel

Bat
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Post by Bat » Tue Nov 23, 2004 8:26 am

uszobajnok, your mixture is 11.7% alcohol: about as much as in a fairly weak wine. That will help but there are various things that can survive that concentration of alcohol, including the bacteria that turn wine to vinegar if air is available (alcohol plus oxygen --> acetic acid).

Bat
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Post by Bat » Tue Nov 23, 2004 8:37 am

DrJ, I agree about adding a pH buffer. I think a redox buffer would be important too, or at least a reducing agent to mop up the oxygen that's bound to seep in slowly, through little gaps or perhaps diffusing through the walls of the tubing.

What are your thoughts on what to use?

A phosphate buffer for pH? Ammonium ascorbate for redox? Thiosulphate? I don't know what's the norm for this kind of thing.

Of course, most people can't get hold of specific chemicals. It's easier to find commercial mixtures that do the same job, and those will have been well researched already and contain all the right things. Examples that come to mind:
# The "life extender" stuff for adding to automotive radiator systems.
# Additives for domestic central heating water.

Any thoughts/comments?

DrJ
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Post by DrJ » Tue Nov 23, 2004 9:43 am

Bat,

I've given no thought to oxygen "scavanging," though redox reagents would work. Choose the redox potential carefully -- I wouldn't think that you'd want to precipitate metals (some of which will dissolve, albeit not much) somewhere in the system.

I don't recall what we added for larger systems for this purpose, but in a sense it was less critical. Big systems limit the amount of "crud" that accumulates by removing a certain amount of water, and replacing it with a clean make-up stream. You don't have that option for the usual small computer water-cooling systems.

I wouldn't use phosphate for the buffer -- that's bug food! Really, PBS (phosphate buffered saline) is a common medium in which to grow microorganisms. Of course, if you use the highest pH equilbirium (12.5 -- phosphate has three, 2, 7, and 12.5) that would probably kill most, but that's higher in pH than I would like to go.

You are looking in the right places for commercial sources. The amount of research these companies have done should be given some respect. There is snake oil on the market, but reputable firms as a rule do good work.

You do have to keep in mind that their products are for other purposes, so they might have components you do not need. Antifreeze, for example, has ethylene glycol (that's the antifreeze part) which one does not really need for water cooling systems for computers unless you are running it pressurized and wish to live dangerously.

Even if you could buy the reagents from a commmercial source (I can), small amounts are VERY expensive. 500 g of "salt" typically costs $50. Strong acids and bases are less expensive to purchase, but require very costly special delivery -- one cannot use the USPS, FedEx, UPS and their competitors. On top of that is a vendor surcharge for any "chemical" purchased (that even includes beach sand and NaCl) -- that covers the vendor's cost to comply with Federal drug enforcment paperwork. And then many of these things cannot be put down the drain untreated, so proper disposal can be another substantial cost.

I know that you are in the UK, but I would guess things are more the same than different.

Ah, life in the times of terrorism and illicit drug manufacturing!

DrJ

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