Hi the tank is about 40 gallons.
in the tank are the 2 mollies, 8 neon tetras, 2 zebra danio, 6 guppies, 2 dwarf gouramies, and 3 bristle nosed catfish.
Regarding the water I'll have to check the levels.
The tank has been fine for years, I guess I have imported an infection with the new fish...