Thanks - yes that does help.
I find those little heaters take ages to heat up the water, so I fill my buckets with treated water and then have to stick them into a hot bath - it's quicker, but not very economical on the heating front... maybe I should time it when I actually have a bath myself... two birds, one stone
I call him a fry but I guess he's about a couple of months old now. They didn't know what he was in the shop so they let me have him in case he got eaten. He hangs out with the neons mostly and is not small enough to be eaten now.
Will my nitrAte actually get to 0 - that would be great. It's always been around 20-30 in my 22 litre. Does that mean I'm not cleaning it thoroughly enough?