KV+Task+3

=__**Water Test: Total, Calcium and Magnesium Hardness**__=

Hard water is a term that is often used when referring to level of dissolved minerals that are present in the water. Water that is considered to be hard, has a high concentration of these minerals. Water that is soft, has a low concentration of minerals. Water hardness is caused by the dissolving of minerals to form ions in the water. Two minerals, calcium and magnesium, typically come from limestone rock that had dissolved into the water. Areas that have high levels of limestone will tend to have high levels of calcium and magnesium.

Water hardness is an important biochemical aspect in the ecosystem. Calcium is one of the minerals that we measure when we detect water hardness. Fish and other species need this important mineral in their daily lives. Some of the reasons they need it is for bone formation and proper blood clotting. This is why it is important that safe levels of these mineral ions are present in the water.

Hard water is also linked to pH levels. Water that has a high levels of hardness, tend to be high in pH as well. This is because the dissolved minerals act as a buffer and can reduce the amount of acid in the water. Water that is low in levels of hardness, tend to be low in pH because there are not as many minerals to help buffer the acid.

Please refer to these and other resources to help you with your research.

Resources [|Understanding Water Hardness] [|USGS - Water Hardness and Alkalinity]

1.) What does it mean when your water is considered to be hard? -Water that is considered to be hard, has a high concentration of these minerals. 2.) Why are water hardness levels important to the ecosystem? -Calcium is one of the minerals that we measure when we detect water hardness. Fish and other species need this important mineral in their daily lives. Some of the reasons they need it is for bone formation and proper blood clotting. This is why it is important that safe levels of these mineral ions are present in the water. 3.) What important ion do fish need to survive? - Calcium, to promote bone formation and proper blood clotting. 4.) What are some potential sources for Magnesium and Calcium ions? -Two minerals, calcium and magnesium, typically come from limestone rock that had dissolved into the water. Areas that have high levels of limestone will tend to have high levels of calcium and magnesium. 5.) Predict: If you have high levels of hard water, how would the pH of the water be affected. - The pH level would be high as well.

Procedure See attached procedure and safety information below. 1.) What are the safety concerns for the chemicals in this lab? - Safety concerns include gloves, eye protection, a lab coat and ventilation. 2.) How do you calculated Magnesium Hardness - Collect water sample - Perform the Total Hardness Test and the Calcium Hardness Test 3 times each. -If results differ by more than 4 mg/l(ppm) Repeat until you have 3 replicates that vary buy no more than 4mg.l.

Data Results for test one was over 200 Test2 --> 100ppm, hardness was 52ppm 100-52= 48ppm magnesium hardness

Analysis Using the internet and other resources, determine what levels of calcium and magnesium hardness are safe for aquatic organisms. (BE SURE TO CITE YOUR SOURCE!) The total alkalinity concentration should be no lower than 20 mg/L CaCO3 in production ponds. Pond pH can swing widely during the day, measuring from 6 to 10, when alkalinity concentrations are below this level (Fig. 1). Large daily changes in pH can cause stress, poor growth and even death of the farmed animals. Most aquatic organisms can live in a broad range of alkalinity concentrations. The desired total alkalinity level for most aquaculture species lies between 50-150 mg/L CaCO3, but no less than 20 mg/L.

--> http://www.ca.uky.edu/wkrec/AlkHardness.htm

Conclusion 1.) What were the challenges of this particular water test? deciding between blue and purple, the reading titrator was a little difficult because the tube was not long enough to completely fill, it had to be pulled. 2.) What might you do differently next time? use a different reading titrator and use different samples., possibly conduct more tests.