We are using Disodium Octaborate Tetrahydrate. There is no chlorine or flourine. I believe the contamination is coming from the cooling process, because the cooling water has a lot of grayish particles but why it leaks through the heat exhanger during the cooling process. We sample the solution...
We are using heat exchanger to heat our borate/ethylene glycol solution to 180 F and cooling it down at 125 F. After it reached the 180 F we heat it further for an hour. We noticed that after 9 batches, the solution becomes grayish(comtamination most probably from the boiler and cooling sytem)...
