what kind of caribsea sand is it? and what kind of rocks/ have you chrcked if the rocks are inert?
A lot of the caribsea sand is meant for marine or African cichlid setups, and contains crushed coral which would buffer your ph. it would also probably increase your water hardness however. you are right that driftwood can soften water, but that is a surprising difference from the tap, and also seems like your water softener is doing nothing. These are pretty puzzling results, I would run the tests again to be sure
A lot of the caribsea sand is meant for marine or African cichlid setups, and contains crushed coral which would buffer your ph. it would also probably increase your water hardness however. you are right that driftwood can soften water, but that is a surprising difference from the tap, and also seems like your water softener is doing nothing. These are pretty puzzling results, I would run the tests again to be sure
