Where do you want your GH levels to stay at??
What type of fish are you keeping?
Got mollies, danios, swordtails, tetras, Pleco, and Cory cats
You've got different fish with different needs...
Livebearers need a GH preferably at or above 250ppm.
Tetras and corys come from softer, more acidic water, as do plecos.
Separate names with a comma.