Pond Boss Forums INTRO Questions & Observations Hardness?

OK, I understand alkalinity but what minerals are present or absent that define hardness?
DD1 says jump in your creek with a bar of soap and see if it lathers?

Or if it causes a fish kill.

I believe that typical hard water contains excess calcium (Ca2+) and magnesium (Mg2+). At least that is what our 300' well water contains. I call it water from hell because it is so hard.

For household purposes a water softener takes care of it.

From a recent thread.

Below is some info and a link. Do you trust the quality of the results? The reason I ask is the big difference between alkalinity and hardness. If the alkalinity is from limestone the numbers are usually similar . Yours are very different. See bold text below. I have only seen that occur where there is acidic ground or well water. As noted below alkalinity is ok at 20 with an acceptable range of 20 - 200+. For Ca hardness the range should be 63 to 250 mg/L CaCO3. I doubt most of yours is from Ca. What is causing the turbidity?

Note the last para below which is obviously not your situation. As a result adding ag lime is a good idea. Do you have high water flow ? If not then I would wonder what is your cause for low alkalinity and high hardness and what is causing the hardness . If it is not Ca hardness the lime will fix that for a while. My guess is to add 2/3 rds of the lime now and the rest in 6 mths. That gives a better (longer lasting ) alkalinity bell curve for effectiveness. If it was my water I would want to know the Ca hardness and what/where the remaining hardness comes from.


SRAC 0464 Interactions of pH, Carbon Dioxide, Alkalinity
and Hardness in Fish Ponds

http://srac.tamu.edu/index.cfm?catid=25

Total alkalinity is expressed
as milligrams per liter or
parts per million calcium carbonate
(mg/L or ppm CaCO3). A
total alkalinity of 20 mg/L or
more is necessary for good pond
productivity. A desirable range of
total alkalinity for fish culture is
between 75 and 200 mg/L CaCO3.
Carbonate-bicarbonate alkalinity
(and hardness) in surface and well
waters is produced primarily
through the interactions of CO2,
water and limestone. Rainwater is
naturally acidic because of exposure
to atmospheric carbon dioxide.
As rain falls to the earth, each
droplet becomes saturated with
CO2; and pH is lowered. Well
water is pumped from large, natural
underground reservoirs (aquifers)
or small, localized pockets of
underground water (groundwater),
Typically, underground
water has high CO2 concentrations,
and low pH and oxygen concentrations.
Carbon dioxide is
high in underground water because
of bacterial processes in the
soils and various underground,
particulate mineral formations
through which water moves. As
ground- or rainwaters flow over
and percolate through soil and underground
rock formations containing
calcitic limestone (CaCO3)
or dolomitic limestone
[CaMg(CO3)2], the acidity produced
by CO2 will dissolve limestone
and form calcium and magnesium
bicarbonate salts:
CaCO3 + H2O + CO2 = Ca+2 + 2HCO3
-
or
CaMg(CO3)2 + 2H2O + 2CO2 =
Ca+2 + Mg+2 + 4HCO3
-
The resultant water has increased
alkalinity, pH and hardness.

Hardness is traditionally measured
by chemical titration. The
hardness of a water sample is reported
in milligrams per liter as
calcium carbonate (mg/L CaCO3).
Calcium carbonate hardness is a
general term that indicates the
total quantity of divalent salts present
and does not specifically identify
whether calcium, magnesium and/or some other divalent salt is
causing water hardness.
Hardness is commonly confused
with alkalinity (the total concentration
of base). The confusion relates
to the term used to report
both measures, mg/L CaCO3. If
limestone is responsible for both
hardness and alkalinity, the concentrations
will be similar if not
identical. However, where sodium
bicarbonate (NaHCO3) is responsible
for alkalinity it is possible
to have low hardness and high
alkalinity. Acidic, ground or well
water can have low or high hardness
and has little or no alkalinity.
Calcium and magnesium are essential
in the biological processes
of fish (bone and scale formation,
blood clotting and other metabolic
reactions). Fish can absorb calcium
and magnesium directly
from the water or from food.
However, calcium is the most important
environmental, divalent
salt in fish culture water. The presence
of free (ionic), calcium in culture
water helps reduce the loss of
other salts (e.g., sodium and potassium)
from fish body fluids (i.e.,
blood). Sodium and potassium
are the most important salts in fish
blood and are critical for normal
heart, nerve and muscle function.

A low CaCO3 hardness value is a
reliable indication that the calcium
concentration is low. However,
high hardness does not necessarily
reflect a high calcium concentration.
But, since limestone is common
in the soil and bedrock of the
southern United States, it would
be reasonably safe to assume that
high hardness measurements reflect
high calcium levels.

My links weren't good enough Eric?

Dwight what is your hardness in mg/l or grains? I'll bet my water is hardner than yours at over 500 mg/l.

Not sure if this is of interest but I can't use my softened water for my 400 gallon RAS fish tank in the basement. Fish prefer hard water and after my softener treatment the hardness reads as 0 on a test strip.

Unfortunately I can't just use my well water right out of the well as it's got too much iron. I'm having a portable iron filter installed Thursday morning. It cost 44 bucks every three months but it will be worth it for make up water for the tank. I did ask for a quote for removing iron from water pumped to the trout pond at 45 gpms but I'm sure the cost will be astronomical. But I'm curious.

Cecil, if your softener uses salt, just add a little baking soda back to it for the hardness. the fish will be less stressed in the salted water also.

I'm lazy I guess. I don't like mixing chemicals etc. and the PHD down the road that makes a living growing out hybrid striped bass for a gourmet market in Chicago told me not to use the softened water.

Our well water is 400 mg/l. The well is also iron bearing. We have a green sand iron filter that takes out the iron before the water goes through the water softener. Then finally for ice and drinking it goes through our R.O. system.

The original shallow well that we used for years was 40mg/l so a water softener didn't have much to do.