My tank has been great, fish have been thriving since I got them in May, and literally just this week my nitrites have been super high! I have been doing partial water changes every day since, as it’s only a 20 call... and this may be off the subject, but water is also very hard (and always has been) but now the ph and kh are low) how do I fix this!? I’ve been feeding less and water changing more, adding prime and am guard! Do I do a bigger water change?