Hi Michael!

Sourdough can be really tricky, and from my experience, there is no 'one size fits all' for how your starter will grow - it can take some starters up to 14 days to start growing. It sounds like you're on the right track; starters can still be revived if there are no bubbles. I would keep feeding it for a while, but make sure it has good conditions to grow. 

Some things to keep in mind:

- You could be experiencing a film due to the starter losing too much moisture. If you are using a paper towel or cheese cloth to cover it, that could be your problem. Try switching to a regular lid for your container or plastic wrap with a rubber band around the lip of the container. 

- Sourdough really likes a warm environment, which can be tricky in the winter. Wrap your container with a hand towel to help preserve some warmth, or move it to a smaller, warmer area. My personal favorite is my oven. Of course, don't turn on the oven to 'pre-warm' it, and make sure to always check the oven before you turn it on to bake anything. 

- Unless your tap water is very hard, you really don't need to use bottled water. When I feed my sourdough, I use lukewarm water from the tap (temperature like you are giving a bath to a baby). 

Personally, I keep my sourdough in a plastic container with a lid and store it long-term in the refrigerator. When I want to revive it, I discard straight from the refrigerator, then only feed (no further discards) for a couple of days until I have good bubbles and growth. When it is growing, I rest the lid on top of the container (without snapping it on) to let it get air while still preserving moisture. 

If you do not have growth after 14 days, I would start over for fear of growing harmful bacteria. You can also check out King Arthur for their tips! https://www.kingarthurbaking.com/recipes/sourdough-starter-recipe

Hope this helps, and good luck!