In article , sburgess63 sburgess6
writes

I have some chillis in another, larger pot that were planted at the
same time but not repotted and their leaves are dark green.

With the repotted chillis the yellowing seems to be "creeping" up the
plants.

Someone suggested magnesium what do you think? Where would I get some?
Any Ideas welcome.

Assuming you potted them in bought compost, it's very unlikely to be a
lack of any mineral in the soil

And I wouldn't expect that to show up in as little as 7 days.
--
Kay
"Do not insult the crocodile until you have crossed the river"