I do a 20 - 25% water change each month. I say 20-25% only because I am not sure how much water is displaced from the original 46 gallon tank after adding sand. I change 10 gallons out each month. My water test results are pH - 8.2<8.4, Ammonia - 0, Nitrite - 0, Nitrate - 5<15.
:) :D :cool: