Well, 50% changes are customary. The reason your nitrite is high is because your ammonia-oxidizing bacteria are working overtime. I'm curious as to where the ammonia is coming from seeing as you're not dosing ammonia. The next change, do a really good vacuuming of the substrate.
Keep doing 50% changes daily until the nitrite is <3.0ppm and watch it, hopefully, decrease.
After reading your post, I wanted to smack myself. For the past two months, I have had two pieces of lucky bamboo, a clump of java moss and a moss ball sitting a 1.5 gallon tank, just adding water to it when it got low. The gravel in the tank is what is left from a prior 10 gallon tank I had, and after testing the veggie tank, I found that the ammonia was a mere .25 ppm and the nitrate to be just about 80 ppm. I am now doing a water change, and I shall be observing it for the next couple of days. If it turns out that I can fully cycle this small amount of water in the tank (the gravel takes up just about half), then I can be just that much closer to having a cycled environment in a five gallon tank.
I actually just had a basic plastic cube tank, no lid on it (so the aeration may have to do with the surface area). I guess also the plants were naturally filtering the water, maybe, big guess on that. I do know, though, where the ammonia supply is coming from. I actually buried some dead plants under the gravel to act as a sort of fertilizer (got that from an anime believe it or not), so the bacteria must have fed off of that for all that time. I threw water from the tap as well, dechlorinated for the plants, and my tap actually has about 1ppm of ammonia in it. I have found out pretty quickly that that 1 ppm of ammonia disappears REALLY quickly.
This is such a great thread, I will certainly be looking at doing a fishless cycle when I am ready to set up a new tank. But one question could you use a raw prawn from the fishmonger. Or where would you get a shrimp? I am guessing its not talking about the small ones in the frozen food cubes.
just had another look actually putting shrimp in the search option. The only shrimp that came up was canned shrimp like Tuna, and it was in brine water. Would one of those shrimps be ok to use, it looked liked it was whole shrimps from the image?
Any rotting seafood will generate ammonia -- any rotting anything, actually. I used a shrimp=sized piece of fresh salmon for my first cycle. It worked fine, BUT...
It generated Saprolegnia mold/fungus which I had to wipe off of everything. And it reeked. I had to keep cling film on the tank to keep the smell out of the room. It took many months for the smell to diminish. That tank stank for a year...until I broke it down and cleaned it. I hear shrimp is particularly vile-smelling.
Do yourself a favor and use "pure" ammonia, that does not foam when shaken.
Better yet, if you're cycling a 5g and up, go fish-in. By using Prime and water changes you are not in any way inconveniencing nor endangering your fish. If you want to do it quickly, use a live bacteria product like Tetra Safestart, API Quickstart or Dr Tim's One-and-Only.
(One of these days I'm going to have to get together with Olympia and revise this sticky to reflect modern technology and techniques.)
Thanks Hallyx's I was planning on doing the fish in cycle, and yes I will get a 5 gal minimum, filter and heater. The reason I was looking at other cycle options is that I believe the betta choices in the UK are likely going to be very limited and I am thinking I will likely be doing a import from Thailand. So was a little concerned it might be too much for a import. Do you think it will still be ok to do fish in cycle with a import. Of course I will be on the ball with the water testing, and water changes, probably checking twice a day. I have checked and can get Prime in the UK, so that will help. It's just that I am reading here that the imports are not as tough as the ones already or bred in your country?