I just put together a 16 gallon planted tank. This is my second planted tank. I didn't have much problem with Co2 in my first tank. The past few days my indicator (I use the Red Sea CO2 indicator) has show too much CO2. However, I won't even have my CO2 on. In fact, the indicator is saying there is too much CO2 and it hasn't even been on for 24 hours. What do you think about this? Do you think the indicator is faulty? The fish seem fine and active. Has anyone had a similar problem? Thanks a lot.