"linda mar" wrote in message
...
Hi all,

I've been trying to figure out what may be stressing my fish... before I
start adding wide-spectrum antibiotics or anti-parasitics, I wanted to
rule
out stuff that is more prosaic than some insidious infection...

If you're going to add medications to a planted tank, be aware that most
medications have negative effects on plants. I never add any medications to
my tank. I guess it depends on what's more important to you, fish or plants.

so I've started to test pH more regularly (every day for the past 4 days).
it's a moderately planted 37G tank, nitrite, ammonia, nitrate is always
zero... temp ~75F.. UGF (2 aquaclear201 powerheadss) + HOT Magnum.

You should probably add some nitrate to help the plants.

so my question is:

1. what would equate to a very diluted 7.6 color? is that considered 7.6?
(basically, no green.. looks like the baby blue for the AP freshwater
nitrite test kit when nitrite=0, but much much lighter than what the card
shows for 7.6). I've tried very high pH (tap water).. and the color
turned
very dark blue, like the 7.6 on the scale.. so..

My guess is that you're not putting the test tube directly against the color
chart card when comparing. If there reflected light coming from behind the
test tube, the color will look washed out and your interpretation will
likely be inaccurate. I have used the AP kit before, and I believe I stopped
using it because the printed colors and the test tube solution colors didn't
match well, and there are gaps between 6.0 and 6.4 and between 7.2 and 7.6.
The Hagen kit works a little better, but the AP one is still pretty usable.

2. can a pH drift from 7.0 to 7.6 in two days when you dont' do anything?
can plants do this? (CO2 outdiffusion, etc) I've heard of water turning
acid, but not creeping to alkaline...

If the KH remained the same, then I believe the pH increase you're seeing is
actually a daily cycle. In the daytime, the plants probably lower the CO2 to
below equilibrium, causing a rise in the pH. Then at night it builds up
again. In that case, you should increase the surface agitation to let the
atmospheric CO2 diffuse into the water better. Without CO2 injection, the
more surface agitation, the better.

3. dKH=2, dGH=6... which is kinda funny.. it was 3, 3 last month. just
tested the the tap and is GH/KH=2... (I use the dechlor'ed tap when I do
partial water change...) so the GH drifted from 2 to 6 in the past month
or
so. is this indicative of something strange with the water? (oddly
enough,
when I checked my LFS's water it was pH7.0, GH=6, KH=2, and we probably
have
the same water source as we are neighboring city.. I wonder if tap
drifted
really high in GH one week when we both did water change?)

You mean the GH drifted from 6 to 2? A drop in GH is usually caused by
snails. When they grow, their shells gather up the calcium from the water.
So a GH drop is due to growing snails and a KH drop is usually due to
nitrification activity.

4. I've added flourish, flourish tabs, flourish iron and flourish excel
in
recommended doses over the past month. can that contribute to GH creep
and
pH instability?

5. should I even *attempt* to increase kH to stabilize the pH from
fluctuating too much? (my idea is less is better for overall
maintenanceship
of tanks... but if it is necessary..)

Increasing the KH in your tank will not stabilize your pH. However, I would
still add some baking soda to make it 3 or 4 degrees, just to be safe from
the KH completely diminishing. To help with the pH fluctuations, increase
surface agitation.
__
Alex R