I would suggest tanking aquarium water, If you have it, like if you already have a tank setup. Take the water from the tank drain it but try to get it kinda clean meaning don't gravel vac just take top to middle aquarium water. This will ensure that there are no chlorines or anything that can hurt the bacteria. Take the bag poor it in a collander/strainer and dunk it in the bucket a few times. That way your aren't rinsing it in fresh water and hurting the bacteria. That should be safe on the bacteria while getting rid of any dust/dirt in the bag.