I do start the plants off in my greenhouse, but these have been outside for at least a month. (North east England) The winter has been very mild this year, only a couple of days of snow !
Looks really very good. From a purely personal point of view, I think I would have a black background if that were mine. Everybody is different, of course.
Get yourself along to a fish auction. Most areas seem to have a couple each year. Hardware tends to go for next to nothing, and you can pick up some first rate livestock very cheaply too.
Thanks for the reply Trev. I did wonder about the effects it would have on Ph, but this can obviously be overcome by rinsing. I feel a project coming on !