I use a weak bloom formula for peppers. Depending on the
nutrient you use, you can use it for the life of the plant. Botanicare's Pure Blend Pro Bloom is perfect for peppers and can be used from seed to harvest. I wouldn't use aggressive fruiting blends, though. They usually lack too much nitrogen. I'm finding FloraMato to be really good for peppers, too. Something else to consider is that they like a low EC. I generally use 1/2 to 3/4 strength nutrient solution depending on the brand and stage of growth.
Sometimes you will get blooms early on and lose them. Especially if your nitrogen levels are too high. Don't worry if that happens. Just make sure to go with your bloom solution. That is the reason I stopped using "grow" solutions altogether on peppers.