This was posted as a mammoth comment by Dave de Witt but I think it deserves a post. Sounds like a labour of love.
Actively Aerated Compost Tea
It’s basically a microbe brew used for foliar feeding and enriching the soil food web. I start from scratch with 30 litres of water which I let stand over night or bubble with air pumps for at least an hour, this is to get rid of chlorine which kills the microbes we are trying to brew. Next step is to add 1tbsp molasses for every 4.5 litres of water, dilute molasses with warm water first. Next, take 1 cup of fresh worm castings or compost (no manure) for every 25L water, 1 cup is fine with 30L, a little more is okay too, but not too much. Wrap the castings loosely in a piece of muslin or similar cloth with loose weave. Suspend it in the water, just below the surface if possible.
Now, I’ve got 2 double output aquarium airpumps and have 1 airstone and 1 airlift pump powered by each pump. Place one airstone directly beneath the suspended castings and the other near one side or in the bag with the castings. Attach the airlift pumps to the side of your “brewer” as deep as possible but make sure the outlet is at least 2cm above the water level, this helps break surface tension and release co2. At this point you may add various other microbial foods such as fruit pulp, fish hydrolizate or rock dust which is great for fungi. Molasses, green plant matter and simple sugars are best for boosting beneficial bacteria. If you have access to Trichoderma or Mycorrhizal fungi spores, add them to the mix when it is ready to apply.
Leave it to brew for at least 12hours, preferably 24, it may have some foam like the brew in the picture, but it might not, this is not a problem. Your nose will tell you if your brew is good, if it smells like a toilet, something went wrong, maybe you need more air, if it smells like it did when you made it, but a bit more “earthy” then it should be good. Once you are satisfied you have a good brew, remove all pumps, stones and the castings. 30L should be enough for a decent sized veggie patch and some pot plants. Do not dilute. To make your tea go further, water the area first and then apply the tea lightly. Pre-watering before applying tea, or any liquid fertilizer for that matter, helps the nutrients get down to the roots where they are needed most. Apply the tea directly to the soil or as a foliar feed. Be sure to clean all equipment used to make the brew asap.
I must make it clear that this is not a nutrient solution, although it contains some nutrients, they are mostly food for the beneficial microbes. Once these microbes enter the soil they begin work unlocking nutrients, feeding on pathogens and exchanging nutrients for sugars with plants. When used as a foliar feed these same microbes occupy sites on the plant where pathogens may take hold, essentially overcrowding the leaves, not leaving any room for diseases or pathogens.
For a detailed insight into The Soil Food Web, I suggest reading Teaming With Microbes by Dr. Elaine D. Ingham.
Hope this helps, let me know if you are curious about anything else.