Well today the first fish went in - 5 Otos from my old cube tank that had been holidaying in the quarantine tank! The Nitrite reading this morning was down to less than 3ppm, but still a slight orange tinge, so I did a 60% water change and very slowly acclimatised the Otos to the tank. I also removed the diffuser to clean it and put the Rhinox 5000 in while I was doing it and immedaitely noticed how much smaller the bubbles were so have left the Rhinox in the tank. Diffusion seems much better now.
And here are two Otos chilling out between meals!
And here are two Otos chilling out between meals!