Originally Posted by
aalbina
Nitrate readings of zero after 12 hours is a little bit suspect ... I would expect it to be at 2-5 ppm. Do have plants in your tank?
How are you testing ammonia, nitrite and nitrate?
What kind of filtration do you have in your 120?
What I meant by pH is what I posted before: here it is again --
4. If you have a pH test kit: take glass of water from the tap, check the pH and record it. Wait 12 hours with that glass of water just sitting on the counter, test the pH of that same glass of water again and record it. If there is no change - wait 12 more hours and test again. The difference in the first pH test and the last will tell you if you need to age your water because of a natural pH swing. If the change is more than .2 then you should age your water. So 6.8 to 7.0 is OK 6.8 to 7.8 is too much - it's actually ten times more not 1 - pH is a logarithmic curve. If there is a big change - then you can age your water or do several small water changes a day. I highly recommend aging the water if you have more than a .2 swing. It will stress your fish over time.
Adam