Convert to dirt with fish in the tank
I have a planted 125G that currently uses black diamond sand as the substrate, as I am sure many of you are well aware of, on it's own it is not a great substrate for growing plants. While I am able to grow some plants, Amazon Swords slowly die off and Crypts just never seem to grow as big as I know they can. So, I am looking to convert it to something more plant friendly. If I go with a dirt tank, then realistically I could re-use some of the black diamond sand to cap the dirt, I also don't re-scape all that often and actually like a tank that looks somewhat unkept / overrun with plants, so the dirt would remain relatively undisturbed. I'll be buying dirt from somewhere like Lowes, rather than digging some up from the back garden.
I am not sure though if I can convert to using dirt while there are fish in the tank, obviously I would need to remove them to a spare 20G that I have sitting empty. That's only going to work for a short period of time though as the fish won't be happy in there for more than a few hours (the biggest thing would be half a dozen Angelfish). The tetras I have would be fine in the 20G, but the angels, yeah, they won't be too happy at all.
So, if I do swap to dirt, will it be OK to put the fish back in again on the same day? If not, then I may use Turface as I have had success with that in the past and don't mind the look.