Re: Increasing Alkalinity

Hi everyone,

Just when I thought I understood the twin concepts of Alkalinity and
Hardness (in all its various forms), along comes something from left field
to show me how truly small my grasp of this topic is.

George Booth has posted that one easy (and cheap) way of increasing the KH
of freshwater without affecting the GH is to use Baking Soda (Sodium
Bicarbonate  NaHCO3). Everything I have read up to this point in time
agrees with this recommendation. Of course, it also shifts the pH of the
water upward (at least in MY water).

The other day I picked up Tetra's book "Aquariology, Master Volume". In it,
it states:

"Sodium Bicarbonate is a pH adjuster rather than a buffer. If added in
excess to an aquarium, the pH can be elevated to unacceptably high levels.
A 10% solution of baking soda can safely be used to raise the pH of an
Also, since Sodium Bicarbonate by itself is not a buffer, the desired pH
may not hold for very long."

So, who's right? Or am I confusing KH (Carbonate Hardness) and Alkalinity
(Acid Binding Capacity)? Am I totally confused yet????

I'm using R/O water, which has no buffering capacity by itself and want to
achieve very soft water (low GH) for my plant tank which is home to my
prized Altum Angelfish. but I want to ensure that the water has sufficient
buffering capacity to avoid any sudden pH drops to below 6.5.

I DON'T want to use phoshate buffers and any product which doesn't list
it's contents makes me nervous. 

I have a bottle of Seachem Reef Builder, which I use for my marine tank.
Would it work (in small quantities)? The label states that it will raise
and maintain alkalinity, restore calcium, magnesium, strontium and trace
elements. It claims to not directly alter the pH of the water and the
contents are listed as Sodium, Magnesium, Calcium, Strontium and Potassium
salts of Carbonate, Bicarbonate, Chloride, Sulphate and Borate.

What do the chemists think? Can this product be used in freshwater tanks
(in appropriately smaller quantities) to increase the Alkalinity of the
water while leaving the GH alone (or at least at a low level)? If not, what
can be used (other than Dupla's KH builder tablets) to accomplish this

James Purchase
Toronto, Ontario
jpp at inforamp_net