Its 20 on the test strips. I use RO water. Im looking at the form of measurement rn and it says mg/LIt honestly seems a bit high. However I am not sure if it's high enough to cause mortalities. You may want to start doing water changes with RO/DI water mixed into your normal water to lower the hardness a bit if your tap water comes out fairly hard.
2 g (full spoon) per 10 litres of water. A ratio of 1.0 gh to 0.5 kh. How many scoops do you think?Ah! Ok, that makes a lot more sense. Then it would be around 1 dDH, so yeah, a bit low! I would aim for around 4-6 dDH, you should see dosing on the product package with a formula for how much salt=degrees hardness. For reference, 1dDH=17.9 mg/L