Re: PH issue

"gizmo" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Well what makes me curious is that just a Day after Changing the water
the
> PH raises....
> I m still looking for factors that might effect the buffering
issue..... I
> came over the hardness issue due to the RO system and this is one good
> thing.
> The only problem is tying to maintain  a PH value of 6.8-7.0 (I m
> optimistic.....)
> I do have 4 tanks which in all I have about the same GH and almost the
same
> PH (7.2-7.4)
> In my planted one I use a CO2 system and its fully planted with not
many
> fish.....
> Maybe I 'm missing something about the buffering but are there other
> parameters I might look for ?
> 10x again
>

If you pH is rising, the kH is rising.  The usual items to verify is any
decorative rocks and the substrate.  Some types of rocks like marble and
limestone will slowly melt raising the kH.  There are many types of
rocks that may do this.  Verify your materials are not of this type.
The usual method is to apply an acid and see if it fizzles.

In a lot of my tanks I use only RO water.  I add tiny amounts of Calcium
Sulfate, Calcium Chloride, and Magnesium Sulfate to insure some
electrolytes.  I adjust my pH with plain Baking Soda.  My pH ranges from
4.0 - 6.0.  Maintaining a precise value has never been my desire.  Since
I have really no kH in the change water the pH floats downward as the
bio filter consumes the kH.  I just try to manage it between these
values adding tiny amount of baking soda as it approaches the lower end
of my range.  I like my water in these tanks to be soft and acidic,
which it is.  I am keeping Angels and Discus in this.  I also have some
tap water tanks and they are hard and alkaline.  Lots of kH settling at
8.2 - 8.4 after the super saturation of CO2 has outgassed.  This takes a
few hours after a water change.  My tap water reads a pH of 7.2 - 7.4
straight out of the faucet.

RO water has no hardness or buffering.  Taking a pH reading is rather
tricky on it.  My $75 pH meter tends to read it rather closely to
whatever the pH of the solution I calibrated to.  If I calibrate to 4.0,
I tend to get levels just above it.  If I calibrate to 7.0, it follows
this closely.  Its hard to read since the probe has an influence on it.
The precision of my meter is specified to be .2, which means its not
pinpoint accurate.  The accuracy is very limited and is easily
compromised.  I understand its short comings and really would not worry
over even a .5 discrepancy.  It clearly is most trusted immediately
after a calibration with a solution close to what I intend to measure.
I would probably spend a couple hundred dollars on a better and more
accurate model if I felt that pH was such a vital parameter, but I do
not believe it is.  My meter is better than a color change test kit and
that's about it.

After mixing water sources it may take a while before the pH is stable
especially in low buffer environments.  RO water will generally take on
the characteristics of the environment its added to, since it has no
buffer.  It will dilute the gH and kH, but cannot really affect the pH
directly beyond the dilution affects.

Not sure why you want your pH to be precisely 6.8 - 7.0 all the time?
That would be really tough to do without adding some type of pH
regulating goop into your tank.  Fish are certainly not so picky that
such a precise value is required.  Some folks are lucky in that their
tap water is at a value deemed perfect so that plain Water changes are
all that is necessary for maintaining a specific value.  If my desired
pH was 8.2 - 8.4, I personally would have it made.

I manage my water conditions mainly with a TDS/conductivity meter.
That's how I gauge its relative hardness and filthiness.  I use this
meter daily and the pH meter maybe once a month or so.  This meter tells
me when and how much water to change.

Good luck.....with your pH issues.