The filter has gone for over a month and it has captured bacteria.
I guess its not used to more ammonia and will take a while to get back.
I'm a little broke. I plan to buy a freshwater aquarium kit and other things to better care for my aquarium.
For now, I will keep with the water changes and use aquarium salt.
You never have to replace sponge filters. Just give them a little rub and rinse in old tank water during water changes. The only time you should replace your sponge filter is if for some reason the media is falling apart.
Lastly, you don't need natural sunlight. Just make sure your bulbs are florescent bulbs.