Thanks Matt, I just calibrated the probe on Sunday when I installed the co2 system and controller; Once I shake loose some more $ I will look into a co2 tester for the water (does anyone have any experience with this and have a recommendation of a good one?) and I might get rid of the wet/dry and replace it with a FX5 canister or C-530 canister filter; Just plug the drain hole in the bottom of the overflow and put the intake for the filter at the bottom of the overflow that way there will not be any waterfall effect; Thanks again, Jeff A. _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member