mysterious fish losses

[Aquamarina]

J&L told me that about 24 pails of IO produced last June, 03 were extremely highly alkaline. I ordered 2 pails last summer and am now about 3/4 through the second pail. I did order another pail last month, and will prob. mix it, test for pH before adding it to the main tank, leave it a week or more, and make sure it isn't leaving sediment on the sides of the glass. J&L have assured me they have heard of no further problems with this product.