Transcript of Heart Disease and the Excretory System. Heart Disease and the excretory Heart disease slows the oxygen flowing throughout the body. So oxygen moves slower to the excretory system.
The most likely causes of a shift in pH are: 1  Something in the water source buffering the water. 2  Something in the tank buffering the water. 3  or Something you are adding to the tank.
This means that if you have a tank running at pH 7 with any of the myriad fish that are happy at a near neutral pH such as tetras, corys, many South American cichlids, kribs, gouramis, rasboras, danios, etc etc. then carbonate rocks are not an automatic no-no, as is often suggested.