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Old 24-06-2011, 04:16 AM posted to rec.ponds.moderated
~ jan[_3_] ~ jan[_3_] is offline
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First recorded activity by GardenBanter: Apr 2007
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Default Sudden ph Drop & Fish Die Off

On Sat, 18 Jun 2011 17:26:07 EDT, JB wrote:

I've been a ponder since 1998. I recently experienced something that I
hadn't before; a fish die off. I lost 4 6-7 inch goldfish in one day and
then one or two more on the subsequent days. My large Koi seemed fine
and the small goldfish appeared healthy as well. I've never lost this
many fish in such a short time for what appeared to be health reasons.
(Snakes and GBH yes but that's another topic.

The weekend before I'd cleaned out my Bio-Falls filter, washed off the
Matala pads, spun plastic filter pads and 4 bags of lava rock and
bio-balls as I usually do once a year. The water was crystal clear, pond
was looking good and then the fish began to die. Initially, I took it as
an unfortunate coincidence and then it continued. Then, I thought that
it might have been because the daily high temperature had jumped up
about 20 degrees from what it had been. (What happened to Spring?)

A friend of mine suggested that I test the water. Me test!? I was beyond
that. Hadn't done a water test in 3 or 4 years. Things were fine, or so
I thought. I dug out my box of test kits and began testing: Ammonia - 0.
Oxygen - great. Ph - 6.0! How'd that happen? At one time years back I'd
used some Ph Down but I never had to raise the Ph.

I did a water change and brought it up a little. I did others on the
following two weeks. Ph is up now and the fish seem fine; no more deaths.

I used to do water changes but I'd not been doing them as regularly as
I'd done in the past. I guess I need to do them a little more regularly,

Yes, agreed on water changes, always. It usually isn't the pH but your
buffering (kH) that is used up and the pH swinging wildly stresses the
fish, water changes, assuming one's source has enough natural buffering,
keeps the kH up in our ponds. ~ jan
Zone 7a, SE Washington State