Gh Levels

[skindog]

anybody know what ratio of R/O water to add to my tank in order to lower G.H.

 

[Bignose]

The calculations aren't hard. Just remember that GH is a concentration measure, so water with a certain GH has a certain about of minerals per unit volume.

I find it easier to think about starting with 1 unit volume (1 gallon or 1 Liter) of water. Let's say the GH in that original 1 gallon is 10 degrees (which is about 178 ppm of hardness). Now, mix in 1 unit volume of pure RO water. So, you have 10 degrees now divided by 2 units or, 2 units of 5 degree concentrated water.

Here is the general calculation: Start with two volumes of water, a volume of A that has concentration x, and a volume of B that has a concentration of y. If you mix those together, you get a final concentration of ( x*A + y*B )/( A+B ) This is the answer as above, just use A=1, B=1, x=10 degrees, and y=0 degrees.

Finally, in order to fill your tank, you know that A+B = the tank volume. So if you know your target GH and the tank volume, you can back calculate what the two volumes A&B need to be.

You have two equations in two unknowns (A&B) assuming you know what the original concentrations (x&y) and target concentration are:

equation 1) tank volume=A+B
equation 2) target concentration = ( x*A + y*B )/( A+B )

If you don't know how to solve two equations in two unknowns, I can post how to do that, too. Just let me know.