For anyone deeply curious about water search the internet for the fanatics
who grow coral in their saltwater aquariums.
--
Dave
Sent with Airmail
On July 12, 2018 at 1:06:19 PM, `Richard Knoppow (dickburk@xxxxxxxxxxxxx)
wrote:
There are a couple of issues here, one of which is whether
really pure water is even necessary, at least for B&W. If you
want to be rid of most mineral content a combination of an
activated charcoal filter and boiling will do the job.
Many water systems now use chloramines to disinfect water. It
is not removed by boiling as is chlorine but is removed by an
activated charcoal filter. There is some controversy as to
whether chloramines do damage to photographic chemistry.
Boiling removes some types of hardness and chlorine. The
water should be brought to a boil for about three minutes and
allowed to cool without disturbing it. When cooled decant the
water for use. Beside removing hardness and chlorine this will
cook any protein matter and it will fall to the bottom of the
container as it cools. It will also remove any dissolved air.
This last can be of importance when mixing developers.
Many commercially packaged photographic solutions contain
sequestering agents to remove magnesium and other metals from the
water and will work fine with most tap water. If you mix from
scratch treated water is probably a good idea.
Activated charcoal filters, like Brita filters, can be
installed on a faucet rather than whole house water softeners
(which may leave salts behind) and are not expensive. Boiling is
not expensive.
On 7/12/2018 11:49 AM, Dave Hornford wrote:
Check carefully what is removed.
Water hardness (alkalinity) is typically not removed by any
simple flow-through filter
