I've been taking iron tablets for about 9 months. After the first three months the results were worse then before medication. I stopped drinking black tea and switched to another brand of meds. Last month a kind pharmacist told me I shouldn't take it after meals, because the absorption of iron is worse then.
Of course, for 8 months I took a tablet after each lunch. (Because I never forget lunch, but I might forget taking my meds.)
Tomorrow I'm buying a bottle of red!