Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
GH and KH are measured for aquariums using 2 common charts (there are other ways to measure these, too)
German degrees of hardness
Parts per million and milligrams per liter.
When you count drops you are measuring by the German degrees of hardness. 1 drop = 1 German degree of hardness = 17.9 ppm.
Parts per million (ppm) is the same as milligrams per liter (mg/l).
8 or 9 German degrees of hardness is somewhat hard water when you are trying to keep soft water animals.
For fish (I do not know if it is the same for shrimp) you want the set the GH as the most important part of the water parameters.
Then make the KH roughly equal to the GH (about 1-2 German degrees of hardness plus or minus).
pH is less important for fish, but maybe it is more important for shrimp. I keep seeing shrimp and pH, but not a lot of shrimp and GH info. Oh well.
If setting the GH and KH in the right area is not enough, then add peat moss, Indian almond leaves, driftwood, oak leaves or other things to the water or the filter. These materials will release organic acids that will help lower the pH. Sometimes they also remove some minerals (peat moss often does, I do not know about the others)
To make the GH and KH lower, blend your tap water with reverse osmosis or distilled water. Try about 50/50 and test. Adjust as needed. Then add some peat moss or other material to the water and stir that. Test in a few hours and again the next day. Run this test out for a week.
If this works then you will need to add some peat moss (or other material) to the filter, and prepare the water ahead of time.
To prepare for water changes make your recipe of RO and tap, and add a pump or air bubbler to keep the water moving. Add some peat moss in a nylon stocking. I use a knee hi of peat moss in a garbage can of water. Let the water circulate overnight. For a 7 gallon tank you might need only half a cup or a cup of peat moss in a 5 gallon bucket.