I started dosing vodka on 11/1/2018. although I don't dose very much. I started at .2 ml and up to .4 and in a day or 2 I will be dosing .9 for a week. but my question is since I started dosing I have started to notice small bubble coming from rocks that have been in my tank since april of this year. whats going on? is it still curing or is it the bacteria that converts nitrate to nitrogen?