Every 7 to 10 days is a fairly standard answer. Some also watch how much water they use to top up the res. each day. Once they "add back" the same amount as their res capacity, they do a full change.
MisterE Reviewed by MisterE on . Help. How often should I or should I change my reservoir water. How often should I or should I change my reservoir water. I need to know this because I plan on starting a crop of 6 plants this week. I'm a noob but i've been reading the threads, but I just can't seem to find the answer. Much help would be appreciated. ~PM_BigBud~ Rating: 5