we use a sand filter.
and do not have problems with ammonia.

that said.

it worked a heck of a lot better last season, with OLD sand in it, that was
sitting in the filter for years,, backflushed perfectly etc.
this year we decide to use NEW sand.. now it gives us "heebies".
it just doesn't seem to grab the stuff going through it, we backflush it &
it seems clear,, restart it & gunk flows into the pond. Hubby read that it
sometimes gets 'channels' in the sand , (grumble). sooo we have resorted to
taking the top OFF of the filter stirring the sand up & then backflushing
it, the gunk then flows out when its supposed to.. the filter is doing its
job, as the backflush is gunky,, but, for some reason it won't backflush
properly on its own.

now as to your ammonia problem,, any chance the sand, for some reason had
some additive to it? maybe you can get another bag of it & test the water
that would sit with it in a bucket ??
even with a TON of toads mating this spring we didn't have an ammonia spike.

btw, we also have a bio filter running,,,,,,,,,,,,,, just to be pond
"politically correct",, nowadays.


"Carl Harrison" wrote in message
m...
Did you accidently kill all the old bacteria in the old filter (left
pump off
too long, let dry out, ...)?

Old filter is working perfectly. Readings in last chamber show zero
ammonia and nitrite, water is then pumped into sand filter and through
to pond where reading is high ammonia. If I bypass the sand filter the
ammonia level in the pond is back to zero in 2 or 3 days.

Maybe I am getting dead spots in the sand ? I will reduce the sand and
try again.

Carl