I have a steel chamber submerged in a 14 deg water bath to keep it at constant temperature. The setup needs to operate without intervention for a very long time (weeks or months).

The bath is exposed to open air in the lab and we have been having issues with mold development in the bath despite adding bleach to the water.

Can you suggest a different additive (or a different liquid altogether) to use to make sure the bath stays reasonably sterile?

  • $\begingroup$ There are additives for, e.g. chilled water loops, to resist bacterial and biofilm build up (which is why processed chilled water is colored, not clear). And, with bleach, you have to keep adding it, not assume it will last forever. $\endgroup$
    – Jon Custer
    Commented Oct 5, 2016 at 12:44
  • $\begingroup$ Hello @jon-custer, thanks a lot for the answer! Could you suggest any brand or product name? I've only been able to find anti algae for aquariums, but I'd prefer something that sterilizes the water as much as possible. $\endgroup$
    – muzzle
    Commented Oct 5, 2016 at 14:53

1 Answer 1


Apparently an acceptable choice of additive is silverised hydrogen peroxide. Only a few 100ppm should be necessary to keep the water sterile and the half life is about 5 weeks.

I'll go with this and update this answer if there are any issues.


This article on overclocking (http://www.overclockers.com/pc-water-coolant-chemistry-part-ii/) has a number of suggestion on water additives to improve the thermal conductivity and keep the system clean.


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