Nikki Casali wrote:
Neil Woodman wrote:
Nikki Casali wrote:
Neil Woodman wrote:
Hi,
If wonder if any of you guys could help me. I did my usual 30%
water change on Saturday night, I got in on sunday to find all of
my tetras swimming near the surface gasping for air, the only thing
I had done differently was increase the CO2 slightly. Then I
noticed some bleeding heart tetras were dead, and then I noticed
some shrimp going a bit strange darting up to the surface and back
down again. Suddenly all the fish started to die in front of my
eyes! There was obviously no oxygen in the water so I added a
powerhead to create some surface agitation and did a 50% water
change. The tank has now gone really cloudy and I've lost most of
my tetras and shrimp, there are only some ottos, a 4 tetras, a
rabble of shrimp and one ram which is hard as nails left alive. So
this morning I rushed to my local aquatic shop. He asked me if the
water had gone cloudy after I explained what happened and it had,
so he then said it was a breakdown in the filter which has caused
all the bacteria to go into the water, which had in turn suffocated
all the fish, he recommended doing a big water change which I had
already done and recommended I use some filter aid to clump
together the particles to filter them out faster, I cant remember
exactly what he said but it was along those lines. Can you guys
explain what might have happened and why? This has never happened
to me before and I've been keeping fish for a long time, to
suddenly see them dying in front of my eyes has been a harrowing
experience.
I use an external filter and pressurised CO2, I dont know if that's
anything to do with it, the tank is heavily planted.
I'm very sad about what has happened.
Do you have any idea what the CO2 level was or the pH? Is the change
water straight from the tap and do you allow the water to stand to
allow noxious gasses to dissipate? My tap water contains high
amounts of CO2 etc. Why do you do large water changes?
A breakdown in the filter causes all the bacteria to go into the
water? I don't think so. The bacteria are already in the water. Did
your filter jam up? You didn't make this clear.
Nikki
Hi,
Thanks for that.
CO2 was about 1 bubble per second or so, ph was about 6.5.
What are your KH and GH? What size is your tank? I presume you live in
the north of UK where water is softer? I live in London. A pH of 6.5
for London water would indicate dangerous levels of CO2. I bubble 2 a
second. This is enough for my 330L tank to reach a pH of 7.25 from 8.1
with masses of plants.
Although the
test kit I have doesn't really measure that accurately in terms of
range my ph indicator I have permanently setup showed nothing
untoward. My tap water has always been ok bar a high level of
phosphate, which I use rowaphos to remove, I'm thinking the rowaphos
suddenly released all the phosphate it had stored up due to it being
totally saturated and used up, I've heard that can happen.
Rowaphos state that releasing all its contents is something it does
not or cannot do. I've used Rowaphos in the past with no trouble.
There seems to be nothing wrong with the filter but the water has
gone really cloudy, I have 4 fish left which are still alive but my
shrimp are perched on top of the inside edge of the tank, literally
out of the water! They don't look too happy either.
My shrimp hate water changes. They go berserk, especially if the water
has come from the copper hot water cylinder.
I have always done large water changes as I do about 30% per week, is
this wrong?
It really depends on the compatibility of your tap water with settled
tank water. My tap water comes out at 7.2 pH. My non-CO2 injected tank
stays at 8.1 pH. So if I'm making big changes to that tank I allow the
water to dissipate its CO2 by bubbling with an air stone until the pH
is closer.
Just a guess, but if your tap water contained a high level of CO2 and
you changed the CO2 bubble rate at the same time this combination
could have given your tank pH a kick to a dangerous lower level.
Regarding pouring dechlorinated tap water into your external filter.
I'd never do it. This could possibly have had the effect you see.
Nikki
It seems odd, its not as if I washed the filter media in tapwater which
I would never do but I wouldn't think that pouring a little
dechlorniated water into the filter would cause all the bacteria in it
to be destroyed, its really confusing I have never had a problem like
this before, even using pressurised CO2 increasing and decreasing it in
the past has never caused a problem at all. Thanks for your advice
anyway I will just have to wait and see what happens over the next few
days. How long do you think it will take to fix?
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