Sinigang na Hipon (Shrimps Sour base soup)

1 onion sliced
3-4 pieces half ripe tomatoes quartered
1 small sachet Sinigang sa Sampaloc mix
200 fresh shrimps(medium sized)
4 cups water
1 tsp salt
200 gms kangkong leaves and tender stalks or spinach leaves or stringbeans

1. Place onion and tomatoes on the water and let boil.
2. When boiling add salt and Sinigang sa Sampalok mix.
3. Add the shrimps.
4. When shrimps are red colored or thoroughly cooked add the vegetables last .
5. Serve hot with a cup of steaming rice.