If you decide not to get a controller, I would recommend getting a permanent
visual CO2 monitor. I just ordered one from Dupla. My pressurized CO2 in
my 55 gal has worked well. The only problem have been when I changed things
and didn't realize the co2 implications. Such as switching from a hang on
the back filter with biowheel to a canister. I almost killed a tank full of
fish when the pH got to 6.0. So, since I am basically lazy and rarely test
my water unless there is an issue, I hope the co2 monitor will keep me out
of future trouble.

Bob
"Blake" wrote in message
...
I have a 155g tank that I'm getting ready to re-plant. I'm going to be
adding a CO2 system to it and am considering a PH controller. I was
wondering if anyone had any advice as to:

1) Whether this is really necessary
2) Which one is better

Thanks,
Blake