I have a plant that has the darker veins on the leaves problem and also
redening of the leaves. I am presuming the first bit is magnesium
defiency and the second is an iron problem? Its a new to us garden,
and a foot or so down is a great chalk collection. I am trying to
improve the soil, but need to sort this problem out.

Is epsom salts the same as I have in the bathroom, if so how much
should I put on?
I used a general purpose fertilizer as it seemed to be the only one
listing trace elements(especially as I wasn't sure if it was a few I
was missing). If it is going to work when should I see a difference?
Is it work using a fertillizer for acid soil to try and make more of
the trace element avilable?

thanks in advance
amber