On the other hand, the sodium metasilicate might have been added to their cleaner, in addition to the TSP, to give it more scouring power. Or possibly it is there as an impurity in large enough quantity to require listing on the label.
Margaret,
Sodium Metasilicate is sold as a replacement for TSP, because it is
a phosphate free cleaner. TSP, containing phosphates, presents a
waste water pollution problem in some areas, as the phosphate can
cause algae blooms. Some locations have banned the use of phosphate
containing laundry detergents since the large quantities of that
stuff (from everyone’s laundry) that ends up in the streams and
rivers, was causing ecological changes. As a result many laundry
products eliminated the phosphates, to comply with the laws. Since
TSP is also a cleaning agent, it falls under that law for that type
of use, and manufacturers then packaged the sodium metasilicate with
labels that suggest it’s the same as TSP. It’s not an impurity or
additive to TSP. It’s a phosphate free substitute. And it doesn’t
work correctly in prips flux. The phosphates in this use (prips flux)
don’t present a problem, since we’re not flushing large amounts down
the storm drains.
Peter