I think the ammonia/nitrite/nitrates are going up because your tank is so big (350g) and there's not enough established media in there. You said you squeezed a filter and used an old filter, but how about any old rocks/driftwood in the tank? If you could put driftwood from another tank in your 350g, that would help boost the good bacteria too. If you don't have any at home, just go to the fish store and ask to buy some already in their tank.
You might also want to buy some bacteria in a bottle. A lot of people think it's no good, but I used it on new tanks and only had good results. The one I recommend is Seachem Stability. It's $10 for 8 oz. bottle and works very well for new tanks.
You might also want to buy some bacteria in a bottle. A lot of people think it's no good, but I used it on new tanks and only had good results. The one I recommend is Seachem Stability. It's $10 for 8 oz. bottle and works very well for new tanks.