I have happy fish! Except for the milk they're swimming in. Had a decent (fun) argument with the teenager at the LFS, he said it was ammonia, I said it couldn't be, he said it must have been, I said I check twice a day and it isn't... He said whatevs, do a water change or your fish will die... I ended up buying some clarifier and either that's working or the bacterial bloom is reaching the end of its cycle, I can see the back of the tank again, anyway. Here's a picture from before the clarifier addition:
Bad news, the blue stricta and most of the hygrophilas have turned to sludge so I had to remove as much as I could. The rest is slowly getting removed each time I feed (twice a day) as it gets caught in the elodea. I also took the duck bill off the filter outlet and added another spray bar with a plug in the end, so now the water sprays across about 80% of the tank, and I added a bubble hose through the bottom. Not sure what's doing it most, but the fish are appreciative (I turn the air pump down to low setting and they seem to stop swimming, so maybe they like the bubbles).
Temp is down to 27 due to a couple of overcast days.
I'm going to let things settle for a few weeks and then add another three Rainbows (if they're in stock anywhere) and 2 male, 1 female cherries - bringing both schools back up to 6. I also had the New Guinean Neon Rainbow catch my eye, but I'm not sure whether I want them in the tank and would have to do some serious research first. I think Neon Tetras in 6 months is still the plan.
Just to clarify, the original blue stricta is doing marvellously, the new one I bought on Friday with the hygrophilas died. I am also still showing 0 Nitrate where I thought there would be about 5ppm.