Okay, so a quick search revealed that some plastics are known to leach and others are not. My 5 gallon jug is a #3 recycleable container (stamped onto the bottom of the jug) and google reveals this means it is made from PVC
which, from what I understand, is safe and should not be leaching anything. (Reefers use PVC
for all their plumbing).
Maybe this needs a closer look as to why the test was producing high TDS
#1 type plastics are to be avoided at all costs...
When subjected to harsh treatment, PVC
is believed to release chlorine. Maybe the bleaching and whatnot caused a release of chlorine and that caused the TDS