MaxSea fertilizer 16-16-16 is a well known fertilizer. It is one of the only acceptable fertilizers for nearly all Carnivorous Plants. Avoid use with Roridula.
1/4 TSP is enough to mix 1 gallon of fertilizer. USE PROPER DEMINERALIZED WATER AS IF WATERING PLANTS.
Foliar spray at your own discretion. Drosera, I generally heavy spray every 2 weeks. Utricularia, HEAVY spray every week. Pinguicula, a LIGHT spray every 2 weeks. Nepenthes, every 2 weeks or never.
Use mixed amount within a week or so, or keep in a dark container. Algae will bloom inside the bottle if left too long and receiving light, ruining your spray. So do not use entire 1/4tsp if you do not intend on using a gallon soon. You can also just mix small amounts until its a light tea color.