Making Compost Tea without compost?

I am a very small scale grower and would like to brew my own compost tea. From what I've read you either need a compost pile or worm bin. Is it possible to use store bought worm castings? Will a big bag of worm casting last more than a year or would I have to throw it out after a month?

My planned mix:
Vegetative mix-
1/3 cup Peruvian Seabird Guano (PSG)
1/3 cup High N Bat Guano (Mexican)
1/3 cup Earth Worm Castings (EWC)
1 TBS. Maxi-crop 1-0-4 powdered kelp extract
1 TBS. Liquid Karma (optional)
1 TBS. Black Strap Molasses
@6 - 7 to Tbs per 1 gallons of water every 3rd watering.

Flowering nutrient*tea*mix:
2.5TBS. Peruvian Seabird Guano
2.5 TBS. Earth Worm Castings
2.5 TBS. High P Guano (Indonesian or Jamaican)
1 TBS. Maxi-crop 1-0-4 powdered kelp extract or Liquid
1 TBS. Black Strap Molasses
1 Tsp Beastie Buds/Openseame/Cha-ching
Dilute as needed. Generally, 6 - 7 to Tbs per 1 gallons of water @ every watering.
Grow medium: Coco/Perlite

I can buy these products at the local grow store but with the only bulk they sell, they will last me a long time.

Also how long will the tea stay good for if I continue aerating it? I heard two days and a week so I wanted a positive answer.

From what I have read, the tea peaks at 48 hours and feeding it more doesn't do as well as putting in the fridge after 48 hours where it keeps up to 10 days. I just used quality organic EWC compost from the hydro store. I guess it keeps and 1 bag lasts me a long time if the wife doesn't spread it in the vegetable beds. Just a handful or 2 for 3 gallons of tea.

But I just brew up microbes.

Please keep us informed on how it goes. I am also looking at switching to tea feedings. And how much water do u start with because otherwise u have a sledge?