Lead is the easiest of all dissolved metals to reduce
while aluminium is the hardest. 50 ppb lead and 200
ppb   aluminium   are   the   highest   amounts   of   these
metals  allowed  in  tap  water.  Therefore  they  are  the
maximum amounts of these metals that you, and your
koi,   are   likely   to   encounter   in   your   tap   water. Aluminium at 50 ppb was also chosen so that there was
a  direct  contrast  in  the  effective  life  of  the  cartridge
when comparing it to handling 50 ppb lead. Thus if we
take the original effective life of the cartridge handling
lead at 50 ppb and call that 100%, we can see how the
life of that cartridge is radically reduced, in percentage terms, when it is faced with ever
increasing performance challenges.       Facing  aluminium  at  50  ppb
the   effective   cartridge   life   is
reduced  down  to  50.54%  of  it’s
original ‘lead’ forecasted life.       Facing aluminium at 200 ppb
the  effective  life  of  the  cartridge
has now dropped down to a very
low  12.64%  of  its  original  ‘lead’
forecasted life.       Where does that leave you for
protecting your koi? It leaves you
with a fundamental and               
unchangeable     law     of     water
filtration.   The   effective   life   for
any purification medium used to
protect   your   koi   will   depend
entirely on the total amount of all
substances in the tap water. It is
important     to     reinforce     that
failure to seek                                                sufficient
information   on   the   amount   of
metals (and other substances) in
the   water   before   choosing   and
installing  a  purifier,  plus  failure
to seek individual ratings for the
effective  life  of  any  medium  on
your  tap  water  (i.e.  finding  out
when  to  change  it)  means  that
your  koi  are  left  in  a  vulnerable and   unprotected   situation.   The facts are as bald as that.       The test results also underline
that    the    huge    gallonage    koi
keepers   sometimes   expect   tiny
amounts of purification media to
treat,   to   protect   their   koi,   are
both unrealistic and                                                            
unachievable.  This  is  one  of  the
reasons why I stress the need for
koi keepers to see whole lifetime test  results.  It  is  the  only  way  to  ensure  that  any
purification    medium    lives    up    to    koi    keepers
expectations for the protection of their koi. It is also an
unfortunate   fact   that   people   selling   purification
systems  do  not  always  understand  the  physiological
needs of fish and the specific needs that have to be met
to  protect  koi.  Domestic  cartridges  impregnated  with
metals  such  as  aluminium.  dioxide  or  silver  may  not
always be suitable for fish. Eg: Probable Fish 50%Mortality of Fish Kill Potable Safe Level Experimental Fish Levels Water PCV Silver: 0.1-0.5µg/l Start at 4µg/l Start at 6µg/l 10µg/l K O I 14

  If metals damage is identified and correct intervention undertaken there is hope!
Healthy Koi after metals have been erradicated from pond and fish have recovered.

Photographs above and below courtesy of Michael Van Neste