Yeast require zinc as a micronutrient. I add 1/2 of a zinc tablet to my 10 gallon batches for that reason. The zinc is rapidly taken up by the yeast. No problem using that as a fix.
I have an old chiller that I should take to the scrap yard. Many splits in that one. I had left it in a shed, and gone overseas for a 1.5 years. Many, many splits in that one. Built a new chiller, and do not leave it outside.