Forced aeration, to revise.

Yup, one featiure of that ultimate fish tank have failed to perform.

Last week, new fishes are added into the community. Then, the fishes starts grasping for air in the surface. A check on the acidic lime stone indicated the carbon dioxide it present in the water. How odd. the 3 stage water crush fails to provide sufficient oxygen exchange for the fishes because the fishes breath in faster than the aeration can do it.

Now I have to pump in air with the use of Air pump. the new possibility is to raise the water head, and this involves modify the entire third level hydroponic to raise the water head.

however, the sub level sewer is still working find. hmm... not the tank have 15 Cardinal, 5 small Clown Loach, 1 big clown loach, one algae eater and 3 cory. Yup. it's all schooling fish, and everyone is peaceful.