are you running your co2 at night? if so set it on a timer, have it turn off when the lights turn off, run a airstone at night to release any of the co2 since you dont need it running without lights
if you dont have any fish in the tank or living creatures besides plants your ok to run the co2 at that level, but at least a day before you bring anything swimming into the tank, turn it off, provide great surface agitation to the tank to air out the co2, then slowly add it starting at 1bps to make sure the fish get use to it, co2 indicators give you an idea of how much co2 is too much but its your fish that will truly tell you if you have too much, most of my tanks my fish are happy and cruising around while my indicated is at bright yellow