I can't keep the water clean.

[Jeff Body]

This is driving me crazy. I can't keep my water from growing stuff.
I just spend 3 days last month cleaning everything. I've replaced all the tubing, I flushed all the gunk out and I've ALWAY used distilled water.

This last round I even put in a table spoon of bleach. And still my tube gets cloudy.

I've got a 5 gallon bucket running into my chiller, through the laser tube, and back into the bucket.

I'm really getting frustrated because I want to take care of things I have. I want to do the right thing.
I just can't figure out how to go longer then a month without growing anything. Lord knows I can't grow grass but I can sure grass some algae332136.

[David Somers]

Jeff,

I haven't had algae problems yet but here are some thoughts on this problem for you anyway.

You said you have a chiller but are feeding its water through a 5 gallon bucket? Just wondering why? Is that a true chiller like a CW5000 or is it a water circulator with a heat exchanger but no active chilling going on, like a CW3000? Just curious. If you are using an active Chiller can you dispense with the bucket? That is just one source of contaminent to the system.

Assuming you need the bucket.....My first thought would be to do a ruthless cleaning of the system. Pull your "Chiller" out where you have full access to it and open it up. Remove any barbed hose connectors or hose connectors that can be removed without unsoldering things. You may have gunk hiding behind those connectors that are not being reached by your flushing methods. Get a bottle brush with a long flexible handle that will fit into the tubes of the chiller. Scrub everything out with a bleach solution and be brutal about it. Nothing cursory. Also scrub the heck out of your external tubing, soak the connectors in a bleach solution and scrub, and if you still need the bucket scrub the heck out of that too. Remember how when you were a little kid your Mom would scrub you down after you had played in the mud all day? Be worse than that!!! <grin> Anything that can be soaked in a bleach solution should be soaked.

Then flush it all with distilled or ionized water. Reassemble it and then fill with either of those water types.

Here is a link to a thread on SMC about using anti-freeze you might find useful.

http://www.sawmillcreek.org/showthread.php?233968-question-about-the-coolant-antifreeze&highlight=anti-freeze

Lastly, I would try to eliminate exposure to light for any tubes or the bucket. (Dan Hintz didn't think that would help in another recent thread where I suggested it and I trust Dan implicitly, but you can do this easily without expense and it wont do any harm so you might try it just for giggles)

For what it is worth, my laser uses a CW5000 chiller which I flushed with distilled water before assembling. I also pulled the barbed hose connectors and cleaned them at the same time. And when I assembled it again I used a black hosing that light wont penetrate. I filled it with distilled water, no antifreeze since my garage has never reached freezing temps. Since then I have not had any problems with algae. I have a CNC that uses water cooling. No chiller, just a bucket circulating water through the system as spec'd by the manufacturer. I have that setup the same way. Black bucket and black hosing. Cleaned and flushed before I reassembled it and filled with distilled water, no antifreeze. No problems with Algae in a year now.

Hope this helps! BTW. Not growing grass is wonderful!! You have a lot more free time since you dont have to mow!! Enjoy it!!!!!! <grin>

Dave

[Jeff Body]

Even thou I can't grow grass I still have to mow the weeds.......
Thank you David for some insight


I have the bucket because I use a 1/4hp aquarium chiller for cooling. The bucket houses the pump. 332159

I'll have to try cleaning it again. I pretty much did what you suggested about 1.5 months ago.
I guess I can try switching all the tubing over to black tubing and see if that helps.

Just sucks because it's a long process to have to clean everything every months or so.
And then I hear people say they haven't had to touch their water for 6+months.

[David Somers]

Anyone else out there have some thoughts for Jeff?? Like I said, I have not had algae in not quite a year yet, but I started with a pretty wicked cleaning to be sure I wasn't pumping something that came with the laser and CNC from China.

Dave

[Matt McCoy]

Silly question, but do you have a lid on the bucket? How are the hoses connected?

[Glen Monaghan]

Well, you _could_ replace the water cooled tube with an air cooled one and totally eliminate the problem ;^)

Or you could add disinfectant such as chlorine, although you'd want to check with someone knowledgeable as to what levels might cause problems if you overdo it

Or you could put a UV light in the loop, one of the type used to treat fish ponds or drinking water, and that would control the algae without requiring you to periodically add chemicals.

[Kev Williams]

I'm an avid boater, and what boaters (and a little research online) will tell you, is that algae needs a light source to grow. Hard to tell for sure from you picture, but it looks like your tube is exposed to lots of ambient light. If so, there's your problem.

I've had my Triumph for 27 months now, and I'm on the original distilled water. My tube is completely shielded from outside light, and the water tubing that came with the machine is similar to surgical rubber, if it's not totally opaque it's close to it. The machine is in my garage shop with very little sunlight, and the chiller and tubing is very close to the wall and pretty much doesn't get overhead light either. Last time I looked, only thing on my tube was a little dust, but that was awhile back...

So now I'm curious, so when I get a few minutes I'm going to check my tube...

Meanwhile, anything you can do to shield your tube from light will only help...

[Bill George]

What we used to do on commercial water towers for AC units, massive dose of Chorine let it circulate and kill the algae, then flush with clear water a couple times and clean up the dead stuff.

Then use a small amount of chorine a couple tablespoons in distilled water. Keep your bucket covered, even the dust in the air can start it growing again.

[Rich Harman]

The only contamination I have had is from stuff growing in the translucent hoses. A few months ago it got so bad that the gunk sloughed off the inside of the hoses and collected in the tube, blocking flow and setting off the alarm. I don't think that a UV light would help - isn't the laser tube already a source of UV? Besides, the stuff growing inside the hoses isn't passing by any UV source to kill it off. I now addd chlorox to the water.

[Dan Hintz]

I'm an avid boater, and what boaters (and a little research online) will tell you, is that algae needs a light source to grow. Hard to tell for sure from you picture, but it looks like your tube is exposed to lots of ambient light. If so, there's your problem.

The amount of UV light a DC tube puts out dwarfs anything from ambient... a DC tube is, essentially, a grow light with a side-benefit of being able to cut things.

[Kev Williams]

I'm not much of a brain on such things, but since laser light is monochromatic, coherent and travels in a straight line, which I take to mean the opposite of ambient "scattered" light which travel in all directions-- doesn't that mean the water in a glass tube laser barely "sees" the laser light?

[Rich Harman]

I'm not much of a brain on such things, but since laser light is monochromatic, coherent and travels in a straight line, which I take to mean the opposite of ambient "scattered" light which travel in all directions-- doesn't that mean the water in a glass tube laser barely "sees" the laser light?

Have you ever watched the tube while lasering? It emits lots of scattered light - you wouldn't be able to see it if it didn't. And that light you see is after it has passed through the water jacket.

[Dan Hintz]

I'm not much of a brain on such things, but since laser light is monochromatic, coherent and travels in a straight line, which I take to mean the opposite of ambient "scattered" light which travel in all directions-- doesn't that mean the water in a glass tube laser barely "sees" the laser light?

The coherent beam is what escapes the end-mirror. but that is a mere fraction of the energy that goes into making that beam. If the beam was everything, you would see a black hole where the tube sits. The glowing plasma surrounding that tube is a mini UV light factory... also a good reason not to stare at it for any length of time.

[John Bion]

This has been a recurring problem on different forums/threads. It is also a recurring issue for me. You just learn to clean it out once in a while and live with it :) The general thought seems to be to add a couple of teaspoons of bleach to the water, but the growth still returns after a while. I have two “sealed” chiller units, no open buckets.

Takes half an hour every six months or so to clean it out, so not a huge issue really.

Kind Regards, John

[Keith Winter]

One quick thought. I could be wrong here, but one observation I had reading this was the people that seem to have little problems are using a real chiller, he's using and aquarium pump. Also the people without problems are likely using their laser pretty consistently every day. Jeff is your laser use less than 20 hours a week and is the pump off when you are not using it?

Could part of the problem be the water is not being circulated fast enough it's almost stagnant increasing fungal growth? (think how fungus grows in stagnet pond vs much less in a river) This combined with the other causes mentioned might explain it further....

[Rich Harman]

The general thought seems to be to add a couple of teaspoons of bleach to the water, but the growth still returns after a while.

The bleach breaks down after a while, needs to be refreshed periodically.

[Bert Kemp]

You can pick up a small jar of test strips at any pool place or borg, they tell you when you have the proper mix.I find I have to add a table spoon of Clorox about every 2 weeks to keep 5 gallons of water algae free



The bleach breaks down after a while, needs to be refreshed periodically.

[Jeff Body]

Silly question, but do you have a lid on the bucket? How are the hoses connected?

Yes i have a Lid on the bucket. It's pretty much a closed loop system with the inlet and outlet both being under water.


Well, you _could_ replace the water cooled tube with an air cooled one and totally eliminate the problem ;^)

Or you could add disinfectant such as chlorine, although you'd want to check with someone knowledgeable as to what levels might cause problems if you overdo it

Or you could put a UV light in the loop, one of the type used to treat fish ponds or drinking water, and that would control the algae without requiring you to periodically add chemicals.

Replacing the chiller with an air cooled chiller isn't an option. My garage gets too hot here in FL to run without an active Freon chiller.


What we used to do on commercial water towers for AC units, massive dose of Chorine let it circulate and kill the algae, then flush with clear water a couple times and clean up the dead stuff.

Then use a small amount of chorine a couple tablespoons in distilled water. Keep your bucket covered, even the dust in the air can start it growing again.

I'm thinking I'm going to have to try this option to clean it as well as getting a brush in the areas where I can fit it.



This has been a recurring problem on different forums/threads. It is also a recurring issue for me. You just learn to clean it out once in a while and live with it :) The general thought seems to be to add a couple of teaspoons of bleach to the water, but the growth still returns after a while. I have two “sealed” chiller units, no open buckets.

Takes half an hour every six months or so to clean it out, so not a huge issue really.

Kind Regards, John

How do you go about cleaning it? What's your process?



One quick thought. I could be wrong here, but one observation I had reading this was the people that seem to have little problems are using a real chiller, he's using and aquarium pump. Also the people without problems are likely using their laser pretty consistently every day. Jeff is your laser use less than 20 hours a week and is the pump off when you are not using it?

Could part of the problem be the water is not being circulated fast enough it's almost stagnant increasing fungal growth? (think how fungus grows in stagnet pond vs much less in a river) This combined with the other causes mentioned might explain it further....

I do have a real chiller with a compressor and freon and I do run the pump 24/7 to keep the water flowing. I'm running the highest flow I can get at about 1 gallon a minute.
But you have brought up another interesting point. I haven't been able to get much business so the laser has been sitting with the pump running. I haven't done any work on it in the last month or so.


The bleach breaks down after a while, needs to be refreshed periodically.

This I didn't know......


You can pick up a small jar of test strips at any pool place or borg, they tell you when you have the proper mix.I find I have to add a table spoon of Clorox about every 2 weeks to keep 5 gallons of water algae free

Well based on yours and the last quote I'm thinking I may have just let the bleach weaken to a point where it's not working.
I'll have to see about adding more bleach every now and then.


These are all great suggestion and I thank each and everyone of you for your input.
Please let me know if you have any other suggestions.

[Keith Winter]

1 gallon a minute flow is not horrible, but still fairly slow, if you're using a 5 gallon bucket that means it takes 5 minutes to circulate the entire thing, assuming the pump just sits at the bottom that's not really how it works, the bottom liquid flows quickly and the top not very much. When I say real chiller I mean a closed system. Like the CW-5000 a lot of people use that. Circulates 13/L a minute which is roughly 3.5 gallons a minute. Or you might even be able to get away with a CW-3000 10/L a minute if it doesn't get too hot where you are at.

However I think the bigger issue is the chlorine issue you mentioned, if you are not re-adding chlorine over time it's losing it's effectiveness. First thing I'd try is using more chlorine, adding a small amount every month. Cheap solution that will very likely fix the issue. However in a last ditch effort, if that doesn't work, then you might consider a closed system.

[Jeff Body]

1 gallon a minute flow is not horrible, but still fairly slow, if you're using a 5 gallon bucket that means it takes 5 minutes to circulate the entire thing, assuming the pump just sits at the bottom that's not really how it works, the bottom liquid flows quickly and the top not very much. When I say real chiller I mean a closed system. Like the CW-5000 a lot of people use that. Circulates 13/L a minute which is roughly 3.5 gallons a minute. Or you might even be able to get away with a CW-3000 10/L a minute if it doesn't get too hot where you are at.

However I think the bigger issue is the chlorine issue you mentioned, if you are not re-adding chlorine over time it's losing it's effectiveness. First thing I'd try is using more chlorine, adding a small amount every month. Cheap solution that will very likely fix the issue. However in a last ditch effort, if that doesn't work, then you might consider a closed system.

Believe it or not that's the highest flow rate I can get. I've tried 3 different pump, each larger then the other. I started with the stock pump and when I installed the chiller I upgraded to a 160gph pump. It pumped the same flow rate (1gpm). Finally in hopes of getting more flow I purchased and installed a 800gph pump and guess what. I still only got a flow rate of 1gpm. I can only assume that is the limit to the diameter of the tubing, fittings, flow meter, and tube inlet and outlet.
I'm going to give it another good cleaning this weekend and start over. This time making sure i monitor the chlorine levels.

[Travis Centers]

Is it algae? If so get a UV Clarifier or make one. Works for a fish pond.

[Scott Marquez]

Is it algae? If so get a UV Clarifier or make one. Works for a fish pond.
If all else fails and you want a green option, drop a fish in the bucket that eats algae.. Grin..
Scott

[Robert Bottemanne]

Mettre quelques fils de CUIVRE dénudés dans le système. C'est le système utilisé dans les laboratoires de chimie !

[Rich Harman]

Mettre quelques fils de CUIVRE dénudés dans le système. C'est le système utilisé dans les laboratoires de chimie !

Is the copper wire used by itself or in combination with some other chemical. In marine applications copper sheeting used to be used as an effective barrier against the likes of teredo worms but algae will still grow on it.

[Kim McIntosh]

Sometime ago someone mentioned using glyphosate. Glyphosate doesn't break down over time (so don't pour it on your lawn when your finished with it) and I've been using a very weak mixture for well over twelve months with no apparent detrimental effects and the water is still crystal clear.

[Kev Williams]

A gallon a minute is fine to cool a glass tube, since the tubes don't hold much water themselves. It might even be more beneficial than a faster flow in a chiller, it's easier to cool slow moving water than fast moving water (which is one reason why car engines have thermostats)... but then, it depends too on how fast the laser is heating the water... :)

So I took a look at my tube and took some pics. Badly covered with dust so I wiped down what I could reach (wasn't going to the beast away from the wall!)...

I don't see any algae, except maybe where the yellow arrow is pointing. Not sure if it's algae, or maybe just reflections from the dirt I didn't wipe off. Otherwise, I'm pleased. The wire connections look great. Other than the layer of dust, the thing looks like new to me. I put this machine in service November 29, 2013...


332726332727332728332729332730

[Dan Hintz]

A gallon a minute is fine to cool a glass tube, since the tubes don't hold much water themselves. It might even be more beneficial than a faster flow in a chiller, it's easier to cool slow moving water than fast moving water (which is one reason why car engines have thermostats)... but then, it depends too on how fast the laser is heating the water... :)

Reverse that... it's easier to chill fast-moving water. The greater the difference in the temperature differential, the more efficient the transfer of energy becomes. Therefore, the faster the flow, the higher the temp differential remains between the cooling tube and the surrounding water.

And engines have thermostats so the water does not flow when the engine is cold, allowing for more efficient combustion... otherwise, there would be no reason to have a thermostat at all.

[Rich Harman]

...it's easier to cool slow moving water than fast moving water (which is one reason why car engines have thermostats)...

There's more time to transfer the heat in slow moving water but it is not more efficient. The transfer of heat from the tube to the water is going depend upon the temperature differential. If the water is moving slowly it will heat up more, reducing the temperature difference and reducing the efficiency. The faster the coolant is moving, the more heat it can carry away.

Thermostats in cars are for regulating the temperature in the engine. Water cooled engines are built to higher tolerances than air cooled engines because the operating temperature will always fall within a known narrow range. This is accomplished by regulating the amount of cooling water that is directed to the radiator vs recirculated inside the engine. The purpose of a thermostat is not to slow the coolant down to make it more effective.

[Kees Soeters]

Just curious: why is everybody using water?? Adding corrosive liquids like bleech? polute their systems with algea? have to change and filter the whole system periodically?
I use the same car coolingfluid for over 4 years now. no coolingproblems, no corrosion, no algea en even in the coldest periods no frozen water (-20 degrees Celcius).. even condensation never appeared (although i can't explain that in correlation with the coolingliquid)..
Coolingliquid prevents corrosion and pollution.
I use a CW5000 on a 60W tube.

Kees

[Rich Harman]

Just curious: why is everybody using water?? Adding corrosive liquids like bleech?...
...I use the same car coolingfluid for over 4 years now. no coolingproblems, no corrosion, no algea en even in the coldest periods no frozen water (-20 degrees Celcius).. even condensation never appeared (although i can't explain that in correlation with the coolingliquid)..
Coolingliquid prevents corrosion and pollution.

What do you mean by "cooling liquid", straight antifreeze with no water - or something like Evans waterless engine coolant?

As I understand it, adding antifreeze to water actually reduces its cooling ability but makes up for it in corrosion resistance, lubricity and lowering the freeze point. Using straight antifreeze would be much less effective at heat transfer than straight water.

If you mean waterless coolant, then that is interesting. The main benefit of waterless coolant is that it can operate at a much higher temperature - the hotter the coolant is, the better it can move heat away from the engine and into the air. That benefit would not be realized in a laser. I wonder what the conductivity of waterless coolant is...

[Kees Soeters]

'What i mean is the stuff you pour in your car's radiator. You shouldn't mix it with water.. The antifreeze is what you pour in your windshield spray-reservoir.
I did some tests in the past for heatexchange-conductivity between destilled water and this coolingfluid (this comes in fluorisent green, blue, pink and even orange):
the difference was less than 2 percent.. I doubt you will notice any difference..

Kees

[Rich Harman]

'What i mean is the stuff you pour in your car's radiator. You shouldn't mix it with water.. The antifreeze is what you pour in your windshield spray-reservoir.
I did some tests in the past for heatexchange-conductivity between destilled water and this coolingfluid (this comes in fluorisent green, blue, pink and even orange):
the difference was less than 2 percent.. I doubt you will notice any difference..

Most engine coolants are meant to be mixed with water in a 1:1 ratio, although some come premixed in the bottle, they are not 100% coolant - and they are commonly labeled "antifreeze". We call the stuff you pour in the windshield spray reservoir "windshield washer fluid".

There are waterless coolants, those contain no water at all, like the Evans stuff I mentioned, but that is not in common usage.

[Kees Soeters]

Oh.. Anyway i bought the blue version as this looked nicer with my blue machine (i couldn't find fluoriscent green so fast and pink??? maybe if i was a girl..)
I didn't mix it with anything and poured that in the chiller... So maybe it is premixed 1:1 with water but we don't have to mix that here. There is nothing written about water on the package either..

I have never seen Evans here in Holland..

Kees

[Dan Hintz]

I did some tests in the past for heatexchange-conductivity between destilled water and this coolingfluid (this comes in fluorisent green, blue, pink and even orange):
the difference was less than 2 percent.. I doubt you will notice any difference.

Straight radiator fluid (ethylene glycol) has a cooling capacity less than 60% that of straight water at the temperatures a laser will run at. Fluid is used in radiators to lower the freezing point of the mixture, something we don't have to worry about (unless you're storing your laser in a cold garage, which is never a good idea). Pure fluid is pointless... while not necessarily harmful if your cooling system can handle the reduced efficiency, there's no gain (and most definitely a loss) in using straight fluid over a mix with water.

[Jeff Body]

Just out of curiousity. I hear vinegar is a great mild cleaner. Removes soap scum, cleans pots and pans.

Is there any problem you can foresee with running a gallon of vinegar in the water?

[Bert Kemp]

Vinegar is an acid don't know how that would play out in the laser.

[Dan Hintz]

Just out of curiousity. I hear vinegar is a great mild cleaner. Removes soap scum, cleans pots and pans.

Is there any problem you can foresee with running a gallon of vinegar in the water?

Vinegar cleans scale (hard water deposits)... I hope you don't have any of those in your system (you shouldn't be using hard water).

[Jeff Body]

Vinegar cleans scale (hard water deposits)... I hope you don't have any of those in your system (you shouldn't be using hard water).

No. I've always used distilled water so there's no scale.

[Kees Soeters]

Straight radiator fluid (ethylene glycol) has a cooling capacity less than 60% Can be that this fluid, i use, is premixed with water.. but there is nothing mentioned on the package that it already contains water, nor that it has to be mixed in a certain ratio with water..

Kees

[Keith Winter]

Oh.. Anyway i bought the blue version as this looked nicer with my blue machine (i couldn't find fluoriscent green so fast and pink??? maybe if i was a girl..)
I didn't mix it with anything and poured that in the chiller... So maybe it is premixed 1:1 with water but we don't have to mix that here. There is nothing written about water on the package either..

I have never seen Evans here in Holland..

Kees

I'm not sure why you guys are wasting your time debating with a guy who choosing his cooling liquid based on the color. :rolleyes: Not exactly a scientific method going on here.

[Rich Harman]

Can be that this fluid, i use, is premixed with water.. but there is nothing mentioned on the package that it already contains water, nor that it has to be mixed in a certain ratio with water..


It would surprise me to not have water. Can you tell us the product you used?

[David Somers]

Keith!

For myself.....the color of my antifreeze is of utmost importance!! First of course, I would not want to upset my wife's fashion sensibilities. Not to mention the potential for legal issues with the Susan Koman foundation for usurping their trademark color. Then there is the FengShui considerations of using such a strong color as pink in that corner of the garage. Fengshui consultants are quite expensive you know. I would need to redo the entire garage layout not to create Chi havoc out there. Chi running amok in a space filled with power equipment??? I shudder at the thought. Plus there is the expense and time involved in working that new color into my shop wardrobe with my Carhart wardrobe consultant. This is big stuff Keith!!! OK????

D

[Keith Winter]

Haha David!

[Kees Soeters]

Ofcourse the color is not important.. but they both stand in the store. Same price, The blue one is till -26 degr.Celcius and the pink one till -20degrees... I never had a temperature below +10 degrees in my workplace so even the lowest temperature is not important.. so then, if you have to choose.. And my laser is blue and i don't like pink...

As i live in Holland and most of you reside in the USA, many of the things that are normal and widely available in almost any store, are not know here, and vice-versa.. So i can mention a brand but that won't be available there..

Kees

[Rich Harman]

As i live in Holland and most of you reside in the USA, many of the things that are normal and widely available in almost any store, are not know here, and vice-versa.. So i can mention a brand but that won't be available there..

If you don't want to specify the product you used, that's fine. It is strange to me that you will take the time to explain why it won't be helpful to provide the information I asked for, instead of just naming the product. It doesn't matter if the product is available in the USA, we can still use Google and other resources to research it.

[Bert Kemp]

So Rich if your so interested google it yourself and research it :D
Anglo-Dutch (ENGHO) car engine antifreeze coolant -25 ℃ 4KG red green Volkswagen Universal
I did also
Radiator Cooling Fluid 52032 (http://www.maxoline.com/our-products/product-listing/item/radiator-cooling-fluid-52032)


If you don't want to specify the product you used, that's fine. It is strange to me that you will take the time to explain why it won't be helpful to provide the information I asked for, instead of just naming the product. It doesn't matter if the product is available in the USA, we can still use Google and other resources to research it.

[Rich Harman]

So Rich if your so interested google it yourself and research it :D
Anglo-Dutch (ENGHO) car engine antifreeze coolant -25 ℃ 4KG red green Volkswagen Universal
I did also
Radiator Cooling Fluid 52032 (http://www.maxoline.com/our-products/product-listing/item/radiator-cooling-fluid-52032)



Is that the stuff Kees used? If so, it clearly says that it is mixed with water.

[Bert Kemp]

Those were just 2 I found doing a quick search there were others:D



Is that the stuff Kees used? If so, it clearly says that it is mixed with water.

[Kees Soeters]

I tried several times to upload the pictures of the container but it seems prohibited..
So i placed them in my dropbox.. Toe see them you can click the next links:
https://www.dropbox.com/s/c36faqx87qwhrwz/Coolant1.JPG?dl=0
https://www.dropbox.com/s/7rcd7uiu0wme2si/Coolant2.JPG?dl=0

The brand is BREGA and water is not mentioned nor that you have to mix it... see the text on de backside (second photo)

Kees

[Rich Harman]

The brand is BREGA and water is not mentioned nor that you have to mix it... see the text on de backside (second photo)


The labeling certainly leaves something to be desired. There is no mention of water at all, how is the customer to know if it is premixed or if it is straight coolant?

Fortunately they list a couple of specs that the coolant meets. ASTM D4656 is a specification for pre-diluted coolants. So what you have there is coolant that contains 50% water.

[Kees Soeters]

thanks... Anyway, it works fine and my machine stays clean, i use the same fluid since februari 2012!. The coolingcapacity is good enough.

Kees