The begining of CO2 injection is harmfull?

[hadjici2]

Over what time period would a swing of pH 9 to 7 and 9 to 8 need to be done so as for the fish not to have a shock?

 

[smithrc]

sounds like a waste of co2 to me - i dont like waste

 

[hadjici2]

If you continuesly run an airstone and a DIY co2 and you have a pH level of 7 does that mean that there is enough oxygen in the tank for the fish to be ok?

When do you know that CO2 levels have reached a toxic dangerous level?