I had my tank for about 3 months now i was a noob and didnt know anything about them i added my fish sum have died most have survived indun daily water changes and 3 months on my ammonia and nitrite is 0 as is my nitrate so is it cycled i always thot it wasnt if it is i want to change to sand can i do this and put fish in bucket will it effect my levels or will it be ok