Hi. My first post on this site. I have a 54gallon planted tank with pressurized co2 injection, my lights are on for about 10 hours a day, with a aerator coming on at night. In the morning my ph will be about 6.9 and when I get home it will be 6.5-6.6 Is this ok for the ph to change this much. In the tank I have 6 ottos, 6 rasboras, 7 corys, 2 rainbows, 3 mollys, 2 flying foxs, 1 killi, 1 german blue ram, a male and female cockatoo cichlid and 1 red tail sword. Everything is going good with no problems just wanted to see if my ph sounds ok. Added the co2 injection about a month ago, definitely makes a difference on the plant growth. Any advice would be great.