Pond Boss Forums GENERAL QUESTIONS Water chemistry alkalinity test ?

I used the "Salifert Carbonate Hardness/Alkalinity KH/ALK profi test kit" found on Ebay to test the alkalinity in my pond. The results were 9.1 alkalinity. I think the highest reading it offers is 15.0, is this a ppm reading and is this a suitable test for my pond water ? the instructions are not clear on either of those questions. or can alkalinity be that low. Just fishing for information before i spend $60.00 on a water test. Any input is appreciated

You don't have to spend $60 to check your Alk/Ph. Go to Wal-Mart and get an HTH 6 way test kit. They're cheap. It'll give you a good idea what you're pond's Alk and Ph are. It'll test for other things you don't need, but you will get Alk,Ph and Hardness, all are very important. If you want to see Nitrites and nitrates, you can get a test kit from Amazon for about $35.

The readings you posted sound more like Ph, not Alk. Everything is measured as ppm, but the Alk should read a minimum of 40ppm (but the higher the better). Ph should range from no less than 6.0 to 8.0, w/ 7.2 being absolute neutral. The higher your Alk the less swing in Ph your pond water will have. If your Alk is lower than 40, you may want to add AgLime to bring it up.

That is not a standard alkalinity range. The normal range is 0 to 400.
Could be pH which is measured 0-14.

See this as it will help you with all aspects of pond water analysis.

Interpretation of Water Analysis
Reports for Fish Culture

https://srac.tamu.edu/serveFactSheet/262

thats what is confusing me the test result numbers but it is an alkalinity test kit. my ph test kit says ph is 7.5 to 8.o

ill give the walmart test strips a try. would those number be in the ball park for hardness test

Were there instructions? Many test kits come with a formula for conversion. No hardness numbers are similar to alkalinity.

Prior to adding lime, my Alk and Hardness were immeasurable and PH would climb to over 9 during the day. After adding 500# of lime the Alk came up to around 60ppm, but my hardness is still 0. My PH stays between 7.2 and 8.0 now. My well water measures better readings of all three with the same test kit, so I'm confident you'll get accurate readings with the strips.

Yes hardness and alkalinity are not identical but scale is similar 0 to 400 and the difference is not easy to understand. Here is a good analysis.


https://srac.tamu.edu/serveFactSheet/112



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.

Eric, If sodium bicarbonate is indeed the cause of a higher alkalinity than hardness, what would be the typical method of raising the hardness?

I've read using gypsum or even rock salt, depending on the case, can be used. I'm assuming a water test to establish the presence (or lack) of NaHCO3 would be needed.

A recent test of my well water indicated an ALK level of 180ppm and Hardness of nearly 100ppm on a litmus test, much better than my current levels of both pond measures. Could an infusion of well water over time along with aeration improve the situation?

Add ag lime or gypsum. From the fact sheet

Hardness
can be a mixture of divalent salts;
however, calcium and magnesium
are the most common sources of
water hardness.

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).

Where hardness is
caused by limestone, the CaCO3
value usually reflects a mixture of
free calcium and magnesium with
calcium being the predominant divalent
salt.
Agricultural limestone can be used
to increase calcium concentrations
(and carbonate-bicarbonate alkalinity)
in areas with acid waters or
soils. However, at a pH of 8.3 or
greater, agricultural limestone will
not dissolve. Agricultural gypsum
(calcium sulfate) or food grade calcium
chloride could be used to
raise calcium levels in soft, alkaline
waters. Expense might be prohibitive
if large volumes of water
need treatment.

So is it just trial and error when adding gypsum to increase hardness or is there a formulated amount to add per acre? I can get gypsum by the bag, but it's kind of pricey. I can add more AgLime, and probably should, but so far it's not improved my hardness at all.

While I'm thinking about it....should hardness be relatively equal to Alk?

Following this.
I'm in the same boat as Mike Whatley.

Everything except hardness looks golden.
Gypsum is definitely pricey and a PITA to apply as a slurry.

I definitely need to add more lime, but what I've added so far hasn't made a dent, hardness wise. Depending on how much gypsum would be needed, I'm thinking I could turn the aerator on and pour bags into the boil and let it do the mixing for me. Then shut it down and let it settle.

May not be the best way, but I've not heard or read where gypsum is hazardous when applying.

Some gypsum can have higher amounts of sulfuric acid in it. It is the nature of gypsum.

PH is Potential of Hydrogen, because hydrogen has one free electron it is used as the measuring molecule. Neutral PH is 7 half way from 0-14. This meaning that there is no place to add or take away any hydrogen atoms. With most soils and solutions 7.2 is perfect with out the loss of any micro nutrients.

Most of the time you can have a neutral PH and high alkalinity if the Calcium, Potassium, Magnesium are tied up with acids and are dissolved in the solution. Milk is an example of this. It can eat the finish off our dinning room table but not harm you when you drink it.

Thank you all for your input. I called the seller of the product and they couldn't answer my question. The manufacturer did not get back with me. And although it advertised as a fresh and saltwater kit there web site has no imformation on there fresh water product. But i did find this on google
" Total alkalinity is expressed as milligrams per liter (mg/L) or parts per million (ppm) of calcium carbonate (CaCO3). In the aquarium industry, total alkalinity may be referred to as "carbonate hardness" or "KH," which is often measured in degrees (dKH) rather mg/L or ppm. One dKH is equal to 17.9 mg/L or 17.9 ppm. "
If this is correct that would put the water at around 160 ppm. I also took your suggestion and bought the test strips from walmart. they test out around 60 ppm. anyway i just wanted to get back with you. i appreciate your help and any further input you might care to share.

60 or 160 would both be ok.

Did not know that about dKH conversion.

My dyslexia was acting up. My multiplier should've been 1.9 not 9.1 the liquid test results show the alkalinity at about 35ppm. The paper test showed about the same today.