In general most shoot for 20ppm or less. For some more delicate species that don't suffer nitrates well, (discus) 10/5ppm is the target. W/C's are the greatest controling factor. Stocking, feeding, filtering also play a role in frequency of maintainance. Knowing the makeup of your source water is often helpful in setting an effective maint. schedule. "T"
In general most shoot for 20ppm or less. For some more delicate species that don't suffer nitrates well, (discus) 10/5ppm is the target. W/C's are the greatest controling factor. Stocking, feeding, filtering also play a role in frequency of maintainance. Knowing the makeup of your source water is often helpful in setting an effective maint. schedule. "T"