pH was 7.3 after lights off for 12 hours. So if it was 6.0 yesterday the co2 was probably more than 30 ppm. Gonna dial it to about 6.4 or 6.3 and see what happens. Say i have a kh of 2, then i had 60 ppm yesterday. Was trying to find info on cardinal tetra co2 sensitivity but the answers varied.
Something about aquariums