I've got well water in my 5 gal hex, and it's hard as a rock. PH is usually 7.6 or higher. I've been running yeast/sugar co2 to intake of filter, and allowing it to run over night. did a ph test again last night, and ph was down in low 6's. too much co2 in the water? i KNOW none of the solution leaked in. i was starting to worry if the co2 was even making it into the water, but due to the ph swing, some is, right? advice welcome.