I mixed my first batch of saltwater a week and a half ago using HW Marinemix and a Brute trash can. I made my first water change the next day and then covered it for the last week and a half. I opened the trash can today and there is a bad smell coming from the can. Not overpowering, but a smell nonetheless. Should i be cracking the lid on the can? Or should i leave the powerhead on constantly? Is this normal?