Thank you Wilder ^^'
I think you must be right about the ammonia. Despite doing twice daily water changes, I'm still getting 0.25ppm ammonia readings. But since adding the second dose of medication last night I got a higher reading of 0.50ppm. So because I'm having to re-ad medication every day, I think this is the cause of the continuous ammonia spikes.
She seems to be doing really well regardless of the ammonia, which makes me hopeful. There's just a slight discoluration between the scales left now, so things are definitely improving.
But I have a bit of a conundrum coming up. I'm away from tomorrow till Sunday. My OH will be able to do a water change tomorrow night for me, but he'll be joining me on Friday. Obviously I can't leave her in the tank till Sunday if the ammonia is going to continue to build. So I think my only option will be to leave her till as late tonight as possible, and then move her back to the main tank.
When I return on Sunday, I'll check her progress and if she needs another course of the medication then I will have to move her back to the hospital tank again.
Can't really think of any other way of doing it. I'd rather be the one to move her tonight, than leave it up to my OH. He's brilliant at helping me, but I'd like to have a good look at her myself, and he might miss something, or not know what to do.
Any ideas?