On Mon, 3 Jan 2011 14:43:09 -0000, Bob Hobden wrote:

They used to use Pyrethrums but probably use something else these days,

Maybe but pyrethroids break down fairly quickly in the enviroment so
presumably are a good choice to add to the water supply to kill of
shrimps.

I have no idea if "Tap Safe" would remove these but thought they were to
remove chlorine.

The labels also say heavy metals, I must admit my "does it really"
alarm is triggered by the claims of "instantly removing" all these
things.

--
Cheers
Dave.