Frequently asked questions.

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Is my water safe to drink? Water protection agencies provide some guidelines for acceptable levels of substances like heavy metals or toxic substances. But there is often no complete agreement on standards. Some substances may have long term exposure effects so deciding on allowable concentrations is tricky. For some substances like salts it is a matter of "taste". In any case it is almost impossible, at least very expensive to test for every known pollutant although there are tests for broad groups like pesticides. One good indication at least for rural supplies is to look at what is growing or living in your source water. If there is a variety of animals and plants and the water is relatively clear this is a good sign. There may well be bacterial contamination which is not obvious so get a test! For rural supplies if the water smells or if there is a lot of algae or weed growth then the water may need testing or treating.

Do I need to filter my water? (Most of these comments refer to farm and rural supplies). Most times the answer is yes. Even rainwater collected from the roof may contain many bacteria although these may not be harmful. Sometimes water may have a milky look because of colloidal clay particles or may be brownish red due to humic acids. Neither of these represents a health problem, its mainly aesthetic. If you are responsible for your own water supply then filtering is like insurance. The stark reality is that there are many chemicals in the environment which can pollute water supplies. Water from different sources eg a bore or a creek or dam usually has a different chemical composition and needs to be treated differently.

What filter should I buy? (Mainly for domestic supplies). Benchtop filters usually have a single cartridge. A plain activated carbon cartridge will remove organic chemicals including those which cause tastes and smells. A dual carbon / resin cartridge will also remove many dissolved metals. The next step is a dual cartridge filter. Fit a sediment cartridge and a carbon cartridge or a sediment cartridge and a carbon / resin cartridge. Dual units are better for farm water supplies where the water contains solid particles. An even better option is a triple cartridge unit which will hold a sediment, carbon and all resin cartridge. For microorganisms and bacteria use either a 0.5 micron carbon cartridge or a 1 micron carbon cartridge with bacteriostatic action.

An even more complete solution is a reverse osmosis filter. They usually have a sediment pre filter cartridge and a carbon post filter cartridge. The membrane itself will remove most very small molecules including metals, salts and microorganisms. For more on water treatment and filters see filters. For help on choosing a home water filter see choosing a home filter.

Will my soil test tell me how much fertilizer to use? Yes indirectly but your soil test will tell you more if you look at all the factors measured. OK its useful to know how much lime would be needed to get the pH up to a certain level. A measurement of exchangeable acidity will help. Micronutrient tests will show up major deficiencies so they are useful. Here is an example. A soil was tested and showed up high levels of phosphorus and adequate levels of most other nutrients. But growth was poor and to grow vegetables large amounts of fertiliser were needed. Without the test the farmer would have continued to apply fertiliser. The real problem had to do with acidity. The soil test showed to what extent the soil was not working.


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