Can you recommend a spray for the leaves, i think it is magnesium deficiency. Also can you recommend a compost or fertilizer to mix in to prevent this problem in future.
Make sure teh compost is kept moist, not wet.
If this is, and has been the case, apply a tomato food or a general plant food, which contains trace elements in cluding magnesium.
Dig in some well rotted compost or manure before planting.