DON'T BUY ANYTHING FROM HARTZ!!!!!! There have been numerous cases of it killing pets, the stuff is garbage (dangerous garbage)! Flea shampoos only kill fleas at that time, they don't prevent fleas, so they are no better than any other shampoo. You need to find some sort of flea preventative, not a shampoo. There are natural products. I've had good luck with just spraying my yard. You have to spray before the fleas show up and repeat it before it wears off. I don't know if that would work for you b/c you live in an apartment and take your dogs to your grandparents. You may just have to go for a topical, sometimes it's the lesser of two evils.
I have to question why you are bathing both your dogs so often and ask what shampoo you are using. I bath my Maltese every 10-14 days (more frequently when he had longer hair), but I used a high quality shampoo. You can't get decent shampoo at Walmart. That's probably why your dogs are itchy. You can find a few good brands at Petmart and some have a money back guarantee.
I have to question why you are bathing both your dogs so often and ask what shampoo you are using. I bath my Maltese every 10-14 days (more frequently when he had longer hair), but I used a high quality shampoo. You can't get decent shampoo at Walmart. That's probably why your dogs are itchy. You can find a few good brands at Petmart and some have a money back guarantee.