I don't see why it would, iron is present in almost all natural water supplys and is added to planted aquariums.
My water supply is 3 parts per million iron and the is ph 6.3 at the source, not quite as high at my tap because of the filters but still very high and have had fish for about 4-5 years now and no suspicous deaths.
I don't have iron sand, just black silica and black satin sand, My water supply is whats high in iron.