I'm still having some issues with nitrates. stalled at 40 ppm. been this way for over 2 weeks now. have done 3 20 g. water changes and still at 40 ppm. I did each one 3 days apart from each other. went to the LFS and they got the same readings. They advised me to try bio-spira again and see if it goes down. they told me I could leave my skimmer running. I ended up turning off my skimmer with the over flow to hang in my tank so the water would flow in to my tank instead of in a bucket.... i'm questioning if I should be adding bio-spira again or just do a 100% water change at this point. any thoughts.