Thusly Elaine T Spake Unto All:

sodium thiosulfate
As stated it should not form insoluble precipitates with iron,
although I have this faint recollection it may do so with lead,
mercury, and silver. I may be mistaken on that, though.

However... Have you considered using ascorbic acid (vitamin C) for
dechlorination?
One knifetip of ascorbic acid powder is sufficient to dechlorinate a
bucket of water, and ascorbic acid is cheap, easily available, works
also with chloramine, biodegradable, and non-toxic. It will drop the
pH a little, but normally not enough to be a problem.