John:
I work a lot with the Wastwater industry and they commonly refer to T=
DS for salts not solids. It seems that the two mean the same thing and I g=
uess it's just a semantical problem. Every citation I can find on the net =
for TDS talks about measuring salts from whatever source. The lab I use fo=
r testing is A & L in Fresno, CA. I asked them about a year ago what TDS =
meant and they said Total Dissolved Salts however, the book they sell to in=
terpret their reports lists TDS as both solids and salts and the index list=
s the same page. So, I'm not as wrong as I thought. That's kind of a reli=
ef.
You know it is funny because Elaine says the biology will take care o=
f the salts. However I have tests that show that ACT worked as it should, =
the plants are healthier and root systems extended yet the salts are higher=
in the soil tests.
Anyway, below is one citation and following your message is another.
Ted Peterson
Earth-Wise/Spirit of the Earth
Dissolved Salts Meters
High levels of soluble salts in the soil can be caused by excessive f=
ertilization, insufficient watering, poor drainage, or by some contributing=
salt water intrusion. High concentrations of soluble salts can inhibit pla=
nt growth and will reduce overall crop yields. Greenhouse plants and other =
sensitive crops may be damaged if soluble salts exceed 2000 ppm.
Soluble Salts, or Total Dissolved Salts, are measured by means of a C=
onductivity Meter. A conductivity reading measures the capacity of a soluti=
on to conduct an electric current and is directly related to the total ioni=
c concentration of dissolved substances in the solution. Thus, the conducti=
vity reading of a soil extract can be converted into a reading of Total Dis=
solved Salts to indicate combined levels of sulfates, chlorides and other s=
alts in the soil. Extract is prepared using distilled water, not included w=
ith meters.
Digital TDS Meter
Waterproof TDS PockeTester 1
----- Original Message -----
From: John Cowan
To: compost_tea_at_yahoogroups.com
Sent: Saturday, April 10, 2004 10:36 AM
Subject: RE: [compost_tea] Re: Water Quality
Ted,
TDS does stand for total dissolved solids
John:
Also See below. . .
Total Dissolved Solids
General Information:
Measures the amount of salt dissolved in the water. Salts are chemical io=
nic compounds. Salts affect the survival chances of marine life through con=
trolling osmotic pressure. If a water body has a high level of salt, aquati=
c pants and animals that are not adapted to high levels of salt will not be=
able to retain water.
Different species require different levels of different salts. Some need =
low levels, while low levels of other salts can be inhibiting to other spec=
ies.
Generally a high flow will lead to lower TDS readings, while a slow flow =
has the opposite effect.
Sources of pollutant?
Dissolved solids occur in:
a.. ground water seepage
b.. industrial and sewage discharge
c.. Urban, industrial and agricultural runoff
Test Method:
1.. Submerge the twin probes of the meter in sample
2.. Record the result as displayed on the LED display in mg/L.
Results interpretation:
Adverse biological effects can be expected in Australia if the result is =
above 1000 mg/L. The desirable limit for humans is 500 mg/L. (ANZECC, 1992)
Received on Sun Apr 11 2004 - 23:15:05 EDT