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Re: Seachem equilibrium and Alkaline Buffer counter-ions

Tarah Nyberg wrote:

> I beleive that I have been getting green water from my nasty texas tap water > that I mix with my RO water to buffer my 180gal plant tank. (time of year 
> for algae bloom or something)  So far it is under control (just a little 
> green) but I was investigating ways to remineralize my RO.

Texas does have some nasty water, doesn't it?  Just the same, I would be
surprised if the tap water you mix with RO was causing green water.

> So, alkaline buffer adds carbonates without sodium. someone on the list
> mentioned it did so with pottasium and calcium carbonates? but the exact
> ratios etc.. are not officially stated on the seachem web site.

The label says "Contains sodium, potassium, magnesium and other
bicarbonate salts."  Unless they changed the formula real recently that
should still be correct.

> Equilibrium re-mineralizes but again I don't know what the counter ions are.
> SO4? CO3? Cl?

Equilibrium is the one that contains no sodium.  The label indicates
that it contains potassium, magnesium, calcium, iron and manganese. 
Nothing on the label identifies the counter-ions, but the label does say
what the counter ions aren't.  The label says specifically that there's
no chloride.  Apparently it also doesn't raise KH, which means that it
contains no carbonate or bicarbonate.  That leaves sulfate as the only
counter ion that I would usually expect.  The sulfates of all the named
cations are soluble, though calcium sulfate dissolves rather slowly. 
The iron and manganese could actually be there as chelates, but the
label does not indicate that there are any chelates present; they may
also be present as sulfates.  In fact, the manganese could just be there
as an impurity in ferrous sulfate.

> I would imagine that Equillibrium also raises the KH and Alkaline Buffer
> also raises the GH a bit.  Is this true?

My reading of the label suggests that Equilibrium does nothing to the
alkalinity (KH); it just raises GH.  Alkaline Buffer should raise the
alkalinity mostly, and GH slightly.

> If so what is the major advantage in using both products? For example could
> I use Acid Buffer and Equilibrium to maintain a pH of 6.0?

Neither Equilibrium or Alkaline Buffer used alone will give you a
balance of salts in the water that is similar to natural water.  A mix
of the two with distilled or RO water would be more similar to natural
water, except that it would be missing chloride and the potassium/sodium
and magnesium/calcium ratios might be unusual.  Seachem's instructions
suggest that you might combine them in proportions so that the
alkalinity (KH) provided by Alkaline Buffer and the hardness (GH) from
Equilibrium are about the same.

Once you have a mix that gives you the alkalinity and GH that you need,
then you should adjust the pH with CO2.  I know that Seachem says you
can adjust the pH by combining Acid Buffer and Alkaline Buffer in
specific ratios, but I can't advise you to use Acid Buffer to adjust pH.

Kevin Zippel devised a DIY mix for reconstituting RO or distilled
water.  If you don't mind DIY chemistry then his formula (available in
the APD archive) provides another way to go, and it would give you a
result with known and readily adjusted amounts of everything.

Roger Miller