Picture posting is enabled for all :)
Thanks!If it is just the lower/older leaves that are going yellow I would not worry.Leaves go yellow once they have served their purpose and younger ones are taking over,some people remove these older leaves but if you let too much sun in it can harden the skins. A lack of magnesium usually shows as yellow areas between the veins rather than all over the leaf.
Just checked and the tomato feed does have magnesium in it. The yellow starts off like spots and then spreads out. It's not on the very top leaves but it is on leaves from about 3/4 down.Should I take a pic?