That smell is the bacteria bloom. I had that, but once the water started circulating in the 10G tank with the 4 filters, the odor slowly dissipated.
- The biggest mistake you can make right now is to CHANGE the water.
Turn off the lights, unless you want to take pictures. Light will only create unwanted algae growth.
Add a heater, turn it up to high 80's or 90 degrees. (My tank was 90 for 5-6 days.)
The key thing I did differently during my cycle, was the constant addition of MORE filter floss taken from my established bio-wheel.
I just jammed as much as much "Seeded" filter floss in the new filters.
I'm not sure if you're supposed to rinse the seeded media, but I did and it didn't seem to hurt anything.
I also did NOT fill the tank all the way. I only put in about 6 gallons of water. Over the course of the week I fed the bettas more and poured in the top half of their water into the tank in cycle.
The girls got to eat more, and it helped speed up the cycle as well. That's another reason I didn't put gravel in the temporary tanks. So I can monitor them for any chipmunking/bloat issues.
- Basically leave the tank alone.