correct. gas our out gassed via the top. Also a skimmer adds o2
Anerobic bacteria use O2
Temperature affects the amount of O2 in your water. Higher temps = less O2
Thiel recommends 75-77 F
Fish respiration reduces O2
Decay of organic matter reduces O2
Unclean filters reduce O2
Overfeeding reduces O2
Overcrowding reduced O2
Using a protein skimmer increases O2
Good water movement at surface increases O2
Algae increase O2