I also use the bulk reef supply lignite carbon .
I never heard of granulated activated carbon causing ph swings .I suppose in a very remote way it could raise it some by clearing the water and thereby increasing the light and photosynthesis,but I don't think using it will have much of an effect on ph.
trd47 ,What kind of carbon are you reading that from?Perhaps it's a carbon source for dosing not filitering?
I never heard of granulated activated carbon causing ph swings .I suppose in a very remote way it could raise it some by clearing the water and thereby increasing the light and photosynthesis,but I don't think using it will have much of an effect on ph.
trd47 ,What kind of carbon are you reading that from?Perhaps it's a carbon source for dosing not filitering?