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Defoaming a Chromic Reduction tank

I work for a metal finishing company that specializes in treating aerospace parts. Several of these treatments involve Hexavalent Chrome, so we of course have a Chromic reduction tank. My understanding is that there are UV sensors at the top of the tank that bounce light off of the liquids surface to determine how full the tank is. Well, it seems that the chrome has a very thick layer of bubbles and/or foam building up on top of it that is constantly making the equipment read that the tank is full when there is very little Chrome in it. My question is, are there any commercially available defoamers that are safe for use in a Chromic reduction tank?

Scott Merritt
Chemist - Eastman, Georgia, USA
June 19, 2011

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Instead, you should look for a more reliable way of measuring your solution level. If you just need to maintain level (instead of measuring level distance), then a teflon float switch is simple and reliable. There are other choices, but I usually find that the simplest solution is the best.

Jon Barrows, MSF, EHSSC
GOAD Company

Independence, Missouri

June 21, 2011