18
The GH is the so-called total hardness or in German Gesamthärte,
abreviated to GH. The GH is the total amount of dissolved minerals like
calcium and magnesium; in practice about 90% of the GH is made up
out of calcium, the remaining 10% is magnesium. These minerals are
important substances for fi sh health but also for a good growth of water
plants. In case of an adequate GH, these minerals do not limit the plant
growth and thus plants can grow optimal. Optimal plant growth is the
natural way for blocking algae growth, and thus an optimal GH is also
important for clear water and keeping away (thread)algae. Thus, test
the GH regularly and refresh 10% of the water weekly.
An optimal GH-value in fresh water (both aquaria as well as ponds) is
between 8 and 12°DH. When the GH is above 15°DH, the water is too
hard and white deposits in the form of lime can occur. You can lower
the GH by refreshing water; fi rst check the GH and add Colombo Fish
Protect to the fresh water. When the GH is lower than 8°DH, you can
increase it with Colombo GH+.
Ammonia (NH
3
/NH
4
)
Test procedure:
1. Take a water sample of 10 ml.
2. Add 5 drops of NH
3
-1 test fl uid and shake.
3. Add 5 drops of NH
3
-2 test fl uid and shake again.
4. Add 5 drops of NH
3
-3 test fl uid and shake again.
5. Wait 15 minutes.
6. Determine the NH
3
-value using the included colour chart.
20ml
15ml
10ml
5ml
15 min
6
5
3
5 dr
ops
20ml
15ml
10ml
5ml
2
10 ml.
20ml
15ml
10ml
5ml
1
4
NH
3
-1
5 dr
ops
20ml
15ml
10ml
5ml
NH
3
-2
5 dr
ops
20ml
15ml
10ml
5ml
NH
3
-3
