Thanks for your reply.
I use the nutrafin liquid test kit and have a little book with all my readings over the past five weeks. I wasn't aware I needed to leave a week of negative readings - I had just 2 days. The melafix bottle had a dose for adding new fish, and I remember adding various...
I have a 25l fluval chi which I cycled using household ammonia as per the a fishless cycling article from another forum. The nitrites and ammonia were zero so I did a 75% water change and tested again (no nitrates, ammonia or nitrites). I added some soaked bogwood and 2 new plants then a few...