Well, Thats sounds very promising.
But that doesn't help your goldfish
right now. they
REALLY need to be in a larger tank/bin than that, even if its just a plastic starage bin without a filter. i suggest at least a 20 gallon container. In an uncycled container, you have to do 100% waterchanges at least once a day. Maybe twice depending on if the ammonia is rising that fast.
Even if you cannot get a large container for them (temporarily)
you simply must fix the source of the problem before you can expext them to get better. If you cannot find or get a larger bin you might want to start doing 50-75% waterchanges
twice a day. Once in the morning and once at night. This way, you will be even more sure that ammonia isn't building up. also, reduce the amount of food you are feeding them, this will help keep ammonia levels lower.
Are you still using salt in the water you add to the tank?
I'm afraid that this is all you can do for now. Without test kits for all the levels, that is.
So, start looking around for something larger to house them in so that ammonia doesn't build up so quick.
Post back soon.