I used to get terrible mag def until I figured that out. I've read that the absolute amount of calcium or magnesium is not that important but you need the right ratio otherwise one will lock-out the other. When I considered the amount of calcium deposits on everything that gets wet I thought that sounds reasonable. I could also solve it by adding relatively large amounts of cal-mag, but then I'm adding a lot of unnecessary calcium and especially late in flower a bunch of N as well (I used Botanicare cal-mag). Being able to add just magnesium is the perfect solution for my tap water. I never use cal-mag anymore, even in flower when the light is fairly close. It was also worse using LED compared to the CFL I had before.
Canna nutes should be available in most places, at least in my part of Europe. I think you're in the UK, right? I've seen that they have a UK website.
Those buds are looking frosty already, should be a sweet harvest.
Here a couple of pics of the mag def I saw. The first picture is before adding cal-mag or mag and the second picture is when I added mag but not quite enough.
hehe we get the good stuff before Amsterdam
... pics later ... my pebbles are done ... gonna repot brie the white cheese
