Something you could try:
when washing hair, use a diluted amount of the Dandruff shampoo. That way it's not so strong.After hair is clean and dandruff free, the next time you shower, use a more basic, residue free shampoo. Alternate them, just make sure that if you have to use the dandruff shampoo, to use sea salt water directly afterwards so that it helps.
I know there are some residue free shampoos online that help with dandruff, my friend has to order it, I can see about finding the stuff she uses and put it up here.
updated by @pann: 07/13/15 03:18:06PM