On Apr 22, 4:11?am, "Erin (Eugene)" wrote:
I went to a movie at around 9:30 PM. My fish tank is near our door (a
sin, I know, but anyway...). When I walked in a bit after midnight, I
immediately noticed that the filter wasn't running.

I'm assuming that it was running when I left--I believe I would have
noticed, and anyway, I think I recall seeing water movement when I was
glancing over there earlier. I remember because upon seeing the
movement, I checked to make sure my loach wasn't bothering his arch
nemesis (a neon) again.

Anyway, so that means that most likely, the filter was off for three
hours or less. The tank has a few plants in it. The water temperature
and whatnot is fine, so it's just the filter that broke.

Anyway, we immediately removed the old filter (though some water
spilled out of it) and turned on the airstone. After a quick trip to
the 24hour walmart for a new filter (Tetra Whisper, anyone used it? I
haven't heard much and our normal brand is aquaclear, but we didn't
have much choice and will check the LFS tomorrow) we now have a
complete tank again. I'm worried about the following:

a) The bacteria. I'm worried the ones in the tank died.
b) The bacteria. I'm worried that by changing the filter stages all at
once, there's going to be an ammonia spike
c) the bacteria. I'm worried about the crap water that spilled out of
the old filter when I removed it.

Anyone have any words of wisdom? We did test the water and the
parameters were fine, but I'm not convinced that the damage would show
up so quickly. Fish seem to be acting normally.

Also, should I do a water change tomorrow, or not?

(XPosted at Freshwater Fish Tanks)

Erin,
HI there.
You caught the filter mishap pretty early on, so your bacteria aren't
all dead. You may have lost some, but probably not enough to make a
huge difference.
Just don't over load your tank with new fish, extra foods, etc.
Absolutely (!!) do a water change. I suggest doing a normal (20%) wate
change and gravel vacuum.
Since debris was accidentally spilled into the tank, it would be wise
not to forget the vacuuming (even if it was done with the last water
change).
The nitrifying bacteria are very sticky. They are stuck (like glue) to
all surfaces inside the tank. The walls, the filter housing box, the
filter material, the tubing,the plants, the decorations, rocks, and
every surface of the gravel. By replacing a complete filter you have
lost a good deal of your bacteria. However, you still have tons on
every surface of your tank.
By vacuuming the gravel you are not removing any of the bacteria, as
they are stuck like glue remember.
You would, however, be removing any possible source of more trouble in
the futrure while the bacteria colonies are building their numbers for
the ones that were lost. I mean, gunk left in the gravel is only going
to create more ammonia for the decreased numbers of bacteria to
convert to nitrite, and then onto nitrates.
This is going to happen anyway, but with the water changes, gravel vac
and a new filter running your tank will be fine.
What size tank is it anyway and what doyou have in it?