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Re: RO Water

On Thu, 20 Apr 2000, Blendia Nawrocki wrote:
> Where can I find your recipe for reconstituting RO water.  I am using RO-DI
> water in my planted 125 Gal tank.  I have been adding some of my well water,
> it has a lot of silica and causes a lot of brown film if I get too much.  I
> need to change the cartridges now.


I pulled the formula from the original letter.  It follows.  The original
letter was message 22 from August, 1999.  This formula is a correction to
a formula that I slapped together for an earlier post.

People have reported problems getting the calcium carbonate to dissolve,
so using this formula might take some patience.  You may want to go back
to the original letter and some of the earlier conversation to get a more
complete background on the formula.

You should be able to get all of these ingredients at a supermarket.  
Epson's salt and baking soda are sold under those names. Calcium carbonate
comes from tablets sold as dietary supplements; use tablets that contain
calcium carbonate and nothing else.  Potassium chloride is sold as a salt
substitute.  Morton's Salt Substitute for salt free diets is nearly pure
potassium chloride.  You can also buy it at nurseries under the name of
muriate of potash or potassium chloride.

For example, if you want to reconstitute 50 gallons of RO water you would
take four and a half 600 mg calcium tablets, crush them and stir them into
the water.  Also, with a 1/4 teaspoon measuring spoon, measure out and mix
in six and a half 1/4 teaspoon measures of epson's salt, four and a half
1/4 teaspoon measures of baking soda and three 1/4 teaspoon measures of
potassium chloride.

To mix 25 gallons you would use half that much, and so on. 

Happy stirring,

Roger Miller


 Chemical                dose/           dose/           measurement
                         100 liters      50 gallons      unit

 epson's salt            3.5             6.5             1/4 teaspoons
 calcium carbonate       2.5             4.5             600 mg tablet
 baking soda             2.5             4.5             1/4 teaspoons
 potassium chloride      1.5             3               1/4 teaspoons

The composition (after the pH drops) should be

                         dose/           dose/           measurement
                         100 liters      50 gallons      units

 calcium                 15.0            14.3           mg/l
 magnesium                4.7             4.6           mg/l
 sodium                   8.9             8.5           mg/l
 potassium               11.8            12.4           mg/l
 bicarbonate             69.4            66.0           mg/l
 sulfate                 18.4            18.0           mg/l
 chloride                10.7            11.3           mg/l

 general hardness         3.2             3.1           degrees
                         57.1            55.0           ppm as CaCO3
 alkalinity               3.2             3.0           degrees
                         56.9            54.1           ppm as CaCO3
 Na/(Ca+Mg+K)            0.27            0.26           molar ratio
 total dissolved solids  79.8            78.9           mg/l