If you did no water change, 8 ppm of ammonia produces enough nitrate to stall a cycle or even kill it off. the way you went about things makes it hard to know what really happened. You most definitely should have see nitrite. It is possible it was so high it read 0 which can and doe happen on hobby grade kits.
Clearly there is more to this all than you have reported. Have you changed water, have you dosed dechlor, what brand kits are you using. Do you show any nioitrates apart from what may be in your tap?
Adding bacteria to 8 ppm of ammonia should likely kill it so you should not have processed any ammonia. to speak of. So I am wondering how accurate you reported results are.
I don't know who suggested a shrimp as I let folks know it is considered one notch above the useless use of flakes and makes a tank nasty more often than not. May I ask why you did not use ammonia?
Had you started out adding the media and dosing the tank with 3 ppm of ammonia you would likely have cycled the tank an a couple of weeks and with only a couple of additions of ammonia.
I really am at a loss to suggest something as I am not really sure what is going on in your tank. The best I will offer is this. You need to reset the tank so we can figure out where you stand. Follow the instructions below:
1. Buy some ammonia for cycling.
2. Do a huge water change. As close to 100% as possible. Dechlor the new water.
3. Test about 10-15 minutes after adding the dechlorinated water. Fill a small clean container with tank water and take your test water from this. Dechlors can interfere with test resuls so it is best to take them soon after adding dechlor. Test for ammonia, nitrite and nitrate if you have the test. If ammonia and nitrite are both not 0 or very close, change a bit more water until they are. Retest all three things again after changing more water. You need to have base readings recorded.
3. Wait at least 24 hours and then use the ammonia calculator on this site to calculate the amount of ammonia needed to make 3 ppm in a tank they is 275 litres. I know your tank is supposedly more, but this number allows for the reductions in volume cause by decor, gravel etc. and the fact we don't fill tanks to the point of overflowing. The wait is to blunt the potential test distorting effects of some dechlors, especially those which state they detoxify ammonia etc.
4. Wait 24 hours after adding the ammonia and do all the tests again and report the numbers here.
This will give us a good idea of where your cycle stands. Knowing that lets one know how to proceed.
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