Bellingen Riverwatch Online Water Quality Monitoring Manual
Part 2. Can be done at the river or at home / school

2.4.1. Available Phosphate test - using DC1500 meter

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Most kits have a DC1500 except:

  • Sue's kit

  • Paul's kit

  • Chrysalis kit

  • Bellingen High School kit

  • Roving Volunteers kit

The Model Number of your colorimeter is shown above the blue buttons on your machine.

Equipment :

  • 500ml water sample

  • 60ml syringe

  • Colorimeter bottle with no blue dot on lid

  • Colorimeter bottle with blue dot on lid

  • Cottonbud

  • DC1500 colorimeter

  • Distilled water

  • Filter and filter holder

  • Latex gloves

  • Liquid waste container

  • Paper towel

  • Phosphate Blue Box

  • Safety glasses

  • Timer

Safety

Phosphate Acid Reagent and Phosphate Reducing Reagent are hazardous substances.

EXTREME CAUTION MUST BE TAKEN!

Important

Do not use cracked or scratched colorimeter bottles.

The tubes are made of special crystalline glass which allows light to pass through without being refracted. Any lint or scratches on the glass will reduce the accuracy of the results. Always dry the glass thoroughly to remove moisture and chemicals before placing it in the colorimetric chamber.

Do not allow moisture to enter the colorimeter chamber as it may cause the colorimeter to corrode and malfunction.

Do not use Phosphate Reducing Reagent powder that has moisture in it or has caked up - check this before each testing day and replace if necessary. Keep this powder in a separate snaplock bag with silica sachets.

Part 1. Setting up the Blank and the Sample

1. Invert the sample bottle 20 times. Set up timer.

2. Draw some water into the 60ml syringe and rinse. Repeat twice.

3. Using the 60ml syringe draw up 40ml of sample water.

4. Using the tweezers, place a 0.45 micron filter paper in the filter holder and attach to the syringe. Gently expel a small amount of water through the filter.

5. Holding the filter and syringe over the colorimeter tube (no dot on lid), rinse the colorimeter tube twice with filtered sample water. If the filter clogs, replace it with a new filter and continue.

6. Fill to 10ml line with filtered sample water. Always hold colorimeter bottles by the neck to avoid putting finger marks on the glass, as this will affect the results.

7. Repeat Step 5, by adding 10ml to line in colorimeter tube with blue dot on the lid.  You should now have two colorimeter tubes filled with filtered sample water to 10ml line.

8. In one of the tubes (with blue dot on lid), use 1.0mL syringe to add 1.0mL of Phosphate Acid Reagent to the colorimeter tube. Cap and invert to mix.

The bottom of the round disc needs to line up with the bottom of the top marking on the syringe.

9. Then, use the 0.1g spoon to add one level spoon of Phosphate Reducing Reagent powder to the colorimeter tube. Do not wet the spoons or allow them to touch the inside of the test bottle or tube.

10. Cap and gently invert until powder dissolves. START YOUR TIMER!

Important

1. Cap and wipe the outside of both colorimeter tubes, making sure they're clean and dry.

12. Wait 5 minutes for full colour development.

Part 2. Scanning the Blank

13. Carefully wipe colorimeter tubes clean and dry before inserting into the DC1500 colorimeter chamber

14. Insert the dry tube which has not had chemicals added to it (no dot on lid) into the colorimeter chamber, being sure to align the index (vertical) line with the arrow on the meter.

15. Close the lid. We now blank or zero the DC1500 with filtered sample water.

16. Push and hold the Power (bottom right) button to turn the meter on.

17. Press ‘ENTER’ to select the ‘Testing Menu’.

18. Scroll to and select ‘081 Phosphate LR’ from menu.

19. Close the lid. Press ‘ENTER’ to select Scan Blank. The remove the colorimeter tube.

Part 3. Scanning the Treated Water Sample

20. At exactly five minutes, insert the tube which has chemicals added to it (blue dot on lid) into the colorimeter chamber, being sure to align the index (vertical) line with the arrow on the meter.

21. Push the ‘ENTER’ button to select Scan Sample.

22. Record on your Results Sheet.

Pack Up

  1. Remove bottle from colorimeter and pour contents into liquid waste container.

  2. Remove filter from filter holder and dispose.

  3. Rinse all equipment with distilled water and tip it upside to drain on some clean paper towel.

  4. Use a cottonbud to clean the 1ml white spoons and then place the cottonbud in your solid waste container.

  5. Press and hold Power button to turn the colorimeter off.

  6. Empty contents of waste container down the toilet.

  7. If testing at the river, remove equipment when you get home and leave it to drain and DRY COMPLETELY before packing it away for next month's testing.

Tip: The colorimeter may appear to switch off but it will have only defaulted to energy saving mode.

  • Phosphorus occurs in natural waters and in wastewaters almost solely as phosphates.

    Phosphorus (P) is a naturally occurring nutrient that originates from plant and animal matter, and is applied as fertiliser to increase plant growth in agriculture. Phosphorus is essential to all forms of life on this planet.

    Sources of phosphorus enrichment may include some detergents, fertilisers (in both rural and urban areas), animal faeces (e.g. from farms and feed lots), sewage and some industrial wastes. High levels of phosphorus and/or other key nutrients may lead to related problems such as nuisance or toxic algal blooms, although some waterways are naturally eutrophic (nutrient enriched).