LaserUser.com Forum (formerly RDWorksLab)

Hello all, I'm new to this and was wondering what I should add (if anything) to the distilled cooling water to prevent organics from growing? How often do you need to change it? I look around the site but I did not see anything addressing this. Thanks in advance. Frank

There is endless debate about what is an isn't good to use in your system. Things get more complicated if your laser is in a space where there is a chance of freezing. Knock on wood for luck, I have not had to use my laser in that situation so I have just used distilled water in a closed loop system (versus an open bucket and aquarium pump) and it has worked fine without growth issues. I change the water a couple of times a year. Tap water has minerals and other things that can promote growth issues. The various additives people put in to prevent growth, clean up growth, prevent freezing, etc., have the potential to induce things such as corrosion issues within the tube, degradation of the plastic tubing, etc. Debate goes on forever regarding the real potential level for damage. You have to read for yourself and try to decide who is making their claim on sound reasoning and data. I just chose to keep it simple until I see a problem that needs solving.

if you have distilled water, you are already ok : plants and algae can NOT survive with "just" water without some minerals to grow.

if you have a bucket that stay in the open, more or less living organisms will get into (aerial contamination), but without any "food" the contamination will be very slow. if you have a cap on the bucket, you are secure : little contamination from outside, and no light to help vegetals to grow.

Because of our mild climate here and the location of my laser I decided not to use antifreeze in my laser, just a 5 gallon bucket of deionized water.

After I filled it up I let the pump run for several hours to try and clear all the bubbles in the tube.
All of the big bubbles passed through quickly but there were still lots of tiny bubbles stuck along the length of the tube that didn't want to go away. I started and stopped the pump lots of times and gently tapped the tube trying to get them to move along but they were pretty persistent even after hours of running.

Finally in the evening I dumped a bottle of Redline "Water Wetter" (a surfactant) in to the bucket with the pump running and within 15 minutes all of the little bubbles were gone! As soon as the Water Wetter got to them they just let go of the tube, joined up to form bigger bubbles and moved right along.

I don't know if there will be any long term disadvantages (like algae growth) to using just a mix of deionized water + Water Wetter but I doubt it. Time will tell I guess...

This article has a lot of information. Hope it helps.

https://lasergods.com/laser-water-coolants-additives/

Aww, hell. From that article it sounds like Water Wetter is one of the last things I want in my laser system. I hadn't considered conductivity of the solution.
I guess I'll be draining and refilling with just straight deionized water this weekend. Rats.

Thanks for posting that article Larry!

Thank you all for your comments. I at least have a starting point for my cooling water.

Larry thanks for that great link.

Frank

Hank Morgan wrote: Thu Mar 28, 2019 refilling with just straight deionized water this weekend.
Thanks for posting that article Larry!

I hope you mean distilled and not deionized.

You are more than welcome!