UK: Manual for Colombo Aquatests General Guidelines
- Always take care that the test tube is clean before use.
- Clean the tube directly after use.
- Take the volume of the water sample as precisely as possible.
- Keep the drop bottle perfectly vertical during dropping.
- Take care that no air bubbles are included in the drops.
For judging the colour of the water sample after adding all the test fluids, proceed as follows: put the test tube on the included colour chart and look through the tube on to the chart from directly above it. Do not look in direct sun light, but at indirect light. Compare the colour of the water sample with the colours on the chart. The closest colour shows the corresponding value. Generally the colours of the sample and on the chart will not be exactly the same, as values in practice will always be between the standard values, as thus a mixture of both consecutive values. Therefore, one should estimate between which co-lours the sample really lies.
In the test where drops are to be counted , like KH and GH, the mo-ment at which the colour changes is the point at which the true value is reached. The number of drops added to reach that point can be converted to the true value. The colour change is reached within one or two drops. Within the one or two drops the sample has an intermediate colour. The true end value is only reached when the colour doesn’t change anymore. These Colombo-tests are calibrated with professional laboratory test, ensuring the most precise test possible.
Phosphate (PO4) Test procedure:
1. Take a water sample of 10 ml.
2. Add 5 drops of PO4 -1 test fluid and shake.
3. Add 5 drops of PO4 -2 test fluid and shake again.
4. Add 2 spoons of phosphate powder (tube with blue cap) and shake.
5. Wait 10 minutes. 6. Determine the PO4 –value using the included colour chart.
Phosphate (chemically abbreviated as PO4) is one of the waste products produced by fish. Phosphate is not toxic for fish and thus is no direct problem for the health of fish like ammonia or nitrite are. Indirectly, phosphate can lead to algae problem as phosphate like nitrate is one of the key nutrients for algae and plants. Plants and algae compete with one another for nutrients and unfortunately plants can’t always win this competition. In such a case algae can grow and even explode in numbers. In a pond this results in either turbid, green water or in mass amounts of thread algae, In aquaria algae can completely cover the glass, stones and even plants, leading to their death. In a marine tank algae can overgrow corals to such an extent that the corals suffocate and die. Although phosphate is basically not toxic, it is highly desirable to keep the level low to prevent algae growth. For fresh water we advise a threshold of 1.0mg/l and for sea water even 0 mg/l. This can best be accomplished by refreshing water; first check the phosphate level of the refreshing water.