Why won't the ammonia in the tank go down?

I'm wondering about your test strips. Ammonia at only 1 ppm would kill your fish immediately, so there's just no way that it could be that high. Perhaps you mean 0.4 ppm? Or maybe your test strips are way off.

The ammonia removing products only turn free ammonia into the less toxic form ammonium, which still reads on your test strip. I suggest trying to wean your tank away from these products, and use only partial water changes and the beneficial bacteria supplements you have (biozyme and stress zyme) instead. You are doing right with your rigorous water changes, it just takes time and patience to get out of the woods.

Don't change your filter media until your tank is cycled completely. When all you are reading is nitrate, then it is safe to occasionally change your filter cartridge to prevent the carbon in it from becoming a phosphate bomb. Until then, you are throwing out much of the beneficial bacteria. Ottocincus really need an established setup to survive, as they are pretty sensitive fish.

You're overstocked, and it sounds like you didn't cycled your tank before adding fish.

I've never heard of a Fire belly Gourami. Most Gouramis need well over 10- though.

Cardinals need 30-gallons.

Otos need 20+ gallons.

I'd suggest returning all of your fish from whence they came, putting your tank through a proper cycle, http://www.aquaticcommunity.com/aquarium/cycling.p... , and stocking with fish that are compatible to both each other and your tank size, http://theaquariumwiki.com/Stocking_a_10_Gallon_Ta...

Skip all of those chemicals you've been using. They won't do any good, and can do quite a bit of harm.

You shouldn't be replacing your filter media either. Simply rinse it in a bucket of aquarium water each time you perform a water change. Every time you throw it out, you throw out a good percentage of your beneficial bacteria as well.

Good luck.