I just learned from a stupid mistake I have been making, and thought I would share it with the collective. My 75 gal saltwater aquarium has been up and running since February, however I have never been able to get the ammonia levels to zero. I kept doing water changes to no avail. I thought maybe things were still dying from my 46 lbs of live rock. I have been mixing fresh saltwater in a heated 10 gal tank, and then pumping it into my aquarium. I decided to test my new salt water and guess what . . . ammonia!!! I then realized that when pumping fresh saltwater into my aquarium, I would sometimes get some water siphoning back into the 10 gal tank, thus contaminating it. Maybe no one else has done this, however thought I would share this. I cleaned my 10 gal tank, the heater and pumps, and will be sure not to let it back siphon again. Fortunately my tomato clown, coral banded shrimp, cleaner shrimp, hermit crabs and astrea snails have all been hardy enough to survive.
Jeff
Jeff