I've been thinking on this one all day. It appears as if all the variables
are covered. My one suggestion for cleaning the lava rock is to put it on a
grill and cook it like a steak: it will burn out any residue that's in the
rocks, and nothing is left after they heat up. It doesn't smell too good,
but it's an extremely effective way to clean the rock, much more effective
than simply blasting it with a hose or power washer. If the pumps were
leaking, you'd notice the film on the water. After the water's been changed
so many times, one would "assume" that anything toxic had been washed out.
To ensure, I'd nuke the pond with a heavy PP dose which would neutralize
most toxins, then maybe put a couple of pounds of activated charcoal in a
knee-high stocking for a few days where there's heavy water flow. Between
the two, if there are any toxins in the water or on the liner, they will be
removed. Because the fish lived in the same water in the house, but died
when placed in the pond, it leads me to believe some of the simple things
like pH differences, water temp change, fish stress in the bag (ammonia?
heat from the sun?) The power washer is suspect, but if you say it hasn't
been used for anything toxic (BTW, fertilizers CAN be toxic . . .) then the
above recommended things would cure that, especially firing up the lava
rock! This is a tough one: everything I can think of has already been tried
or eliminated. I'll keep thinking, and maybe someone will trip over the
answer.

Best of luck,
Lee

wrote in message
...
please cross post as he really needs help. Ingrid

(Timothy Tom) wrote:

I have a 150 gallon outdoor pond. It was populated by 3 koi, and a
small catfish for over a year and a half until the automatic refill
was inadvertantly turned off. When it was turned back on the fish
died the next day. I assumed it was from a large influx of
chlorinated water. Anyway, I took the opportunity to totally clean
out the pond including about a inch of sludge, and small rocks on the
bottom. New water was added, dechlorinator/conditioning solution
added, and the pond was left to circulate for 48 hours. New koi were
added (after acclimation) and died within 1 hour. I changed the water
3 complete times, reconditioned the water, let it circulate for 1
week, added some comets which died within two hours. I changed the
water again three times, let it circulate for 3 weeks, took a water
sample to my local LFS. They told me that the ammonia was slightly
high (but not deadly) pH, was about 8.1 (slightly high but not
deadly). Basically they told me that they did not know why the fish
died. Using the same tap water that the pond is refilled from, I
placed some comets which lived for a week without problem in a bowl in
my home. When placed the comets in the pond, after acclimation they
died within a day. WHAT IS GOING ON? It appears that there is
something quite toxic to fish in the fish pond. Still I have changed
out the water multiple multiple times with no improvement. The toxic
substance must be specific to the pond, since the tap water did not
kill the fish in a fish bowl. The only things I have in the pond are
two pumps (one is a new fountain pump (Beckett) and the other is the
waterfall pump which has been there for two years without problem.
The pumps are on GFI circuits so I don't think there could be a large
short circuit. There are Lava type rocks in the pond which, once
again were in there with the koi for over a year without problem. I
did power wash the rocks prior to putting them back in the pond. The
water temp is in the low 80's. The water is perfectly clear. Please
any help appreciated since I am at a loss what to do next.



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