CO2 diffuser problems
 

When I first started using my CO2 system which has a Ph controller, a 5 lb.
CO2 cylinder, a CO2 diffuser, it easily monitored and kept the PH down to
7.2 which was ideal for my planted aquarium.

It has been about 8 months now and I am noticing that my PH is now climbing
to 7.7 and the CO2 is not knocking the PH level back and my CO2 is running
all the time. I looked at the CO2 diffuser sponge at the bottom of the
diffuser and saw hundreds of little bubbles under the sponge. It appears
that the sponge is maybe worn out or something. I clean it out under water
every 2 weeks. Do I need to replace the sponge in my diffuser? Because it
is no longer diffusing the CO2 into the aquarium properly? I need some
advise and help.

Dan