Ok, that's enough for a start.

#1 - Stop trusting your dealer (BioGuard?); stop worrying about alkalinity or pool "balance", at least for now.
#2 - ignore your TDS results.
#3 - get a cheap OTO / phenol red test kit (Walmart, whatever)
#4 - get 20 gallons of plain 6% household bleach; start adding them 5 gallons at a time IN THE EVENING within 2 hours of sunset.
#5 - use your OTO kit to test 1 hour after adding bleach, and again in the AM, but no more than 2 hours after sunrise.
#6 - report results here.
#7 - keep your pH between 7 and 7.8, but do not use any other chemicals.
#8 - if it can fit your budget, get a K2006 or 2006C kit for future testing (Amazon links below)

Ben