Originally Posted by roka64
... I would say, if you have nitrAtes present and no ammonia or nitrItes in your main, you are good to go and can seed the biowheel in the main.
I can think of a case where that wouldn't be true.
You cycle the main tank, see the ammonia and nitrite spike and then go to 0.0 ppm
, and finish with some level of nitrates... let's say 10 ppm
. You now let your tank go 4 weeks without adding anything to create ammonia, and you don't do any water changes. Your water parameters now should be the same as when you left it, 4 weeks ago - 0 ammonia/nitrite and 10 nitrate. That doesn't mean you have any bacteria left though.