Furrow Pump, Inc.

P.O. Box 1849

8525 SW St. Helens Dr.

Wilsonville, OR 97070

Phone: (800) 937-3666

FAX: (800) 377-9960

www.furrowpump.com

TitleApplications.jpg (5926 bytes)

JAR TESTING MADE EASY

Jar testing is a method we use to create a proportion. How much of a given chemical is needed to effect the change you want in a water sample? For example, how much of a given concentration of sodium hypochlorite would you have to put into a known volume of water to get a residual chlorine level of 0.5 parts per million? Or perhaps, how much soda ash would you need to put into your water to raise its pH from 6 to 7?

I originally suggested that sizing and selecting a chemical pump would be greatly simplified if some jar tests could be done. Then I realized that many people didn’t know how to do jar testing. Another problem was how to gather the necessary equipment and chemical, or if they were even available in their locale. Since making jar testing easy is to everyone’s advantage, I’ve put together an equipment kit (Table 3), a choice of testers (Table 4 and Table 5), and a way to do equivalent testing with chemicals you can pick up at your local grocery store.

TABLE 1

JAR TEST FACTOIDS

One level teaspoon equals approximately 5 grams of dry powder, or 5 ml of a water-based solution. Two teaspoons are approximately equivalent to 10 ml.

If you count the number of drops from one of your pipets needed to put 1 ml into your 10 ml graduate cylinder, you can verify the number of drops per ml you’re actually dealing with.

For chemists, Normal solution concentrations such as used in Table 2 (See also Explanation: Relative pH Solution Strength & Normality) relate equivalent reaction amounts. One of this equals one of that. It’s a chemical definition, but it works for proportions.

A 5 % soda ash solution, by weight, is closely equivalent to ½ pound of soda ash dissolved in one gallon of water. You can make up solutions as strong as one pound per gallon, but it will require regular mixing to stay in solution, and you may run the risk of plugging up your pump and plumbing.