I realised my cat has got fleas about 2 months ago, I've been successful in treating the house, as I've had no bites for about week now, but when checking the cat with the comb I'm finding live fleas on him, I've used Bob Martin one spot, Wilkinson one spot and Johnson's powder, and a Bob Martin collar, over the last 2 months. I was just wondering how long should any of these take to work and if there is anything better I could do or buy