Hi Mark, thanks for the info. I recall TSP was removed from Catrol Super Clean a while back (causing it to be less effective than previously), and I tried to go buy straight TSP at my local hardware store a couple of years ago and could only find the TSP substitute - without phosphate.
I just searched TSP online and found it on the Home Depot site. When I clicked 'Add to Cart' it stated that none was available at my store (Albany, NY) but there was some at a HD in Bennington, VT and also at two stores in Massachusetts.
Leads me to believe that TSP is unavailable in New York State. Apparently it is banned in some places because the phosphate is a great fertilzier and causes excessive algae and plant growth (around waste water run-off, I presume?).
Thanks for the lead, though. I will try to get some TSP the next time I'm in Massachusetts...