Turn the stove on to a medium high heat.
Place butter in the pot and allow to melt completely.
Add shrimp with the lemon juice it was in into the pot and cook for 3-4 minutes or until the shrimp completely change color.
Remove the shrimp from the pot and leave remaining juices in the pot.
Now you will make the base of the soup. Add sofrito, tomato paste, pimientos, oregano, pepper, salt, Sazon, and onion. Simmer for 2 to 3 minutes. You will notice the base will become thicker.
Once the base simmers for 2-3 minutes, add in the 8 cups of water and mix it well.
Add the remaining tablespoon of adobo and give everything a nice mix and let everything come to a boil.
Once the soup begins to boil add the diced potato, rice, 1/2 of the cilantro, and kielbasa. Let everything come to a boil again.
Once the soup begins to boil, cover the pot and turn the heat all the way down to low.
Let the soup cook for 15-20 minutes. (depending on the consistency you want your rice to be, for softer rice do the 20 minutes...that's my favorite)
Take the lid off the soup and add in shrimp and the remaining cilantro. Cook for about 3 additional minutes.
Finally, serve your soup in a bowl with a side of tostones or avocado and enjoy!