Green water culture- the constant struggle

[Kat_Rigel]

Either you have it and want to get rid of it, or you want it and can't grow it. 😂 For me it is the latter.
I have read multiple online sources for how to start a greenwater culture, but it's not really working out. First, I am too cheap to go and specifically buy Mircacle grow fertilizer (I would use a pinch for this greenwater culture and then have a bag leftover.) I DO have a different plant fertilizer, Scott's slow release fertilizer, with a 10-10-10 ratio. Do you think this would work?
I tried using old aquarium water with a bit of lettuce in it, outside on my balcony with no aeration. (3rd floor apartment) It became a gross goopy slimy mess, but no algae. After 3+ weeks I called it a loss. I am wondering if my balcony just doesn't get enough sun, but I've managed to grow a really tough pair of pepper plants (like, I stopped watering them and they survived the winter in Northern CA.) So it seems like that ought to be enough sun, right? Hornwort and other easy plants are growing ok in my makeshift 29gal pond too (also on balcony.) I am using a rather small container for the culture, like, maybe a half gallon, if that. Is this too small to start a culture? Space is kind of at a premium so I would rather not place an entire aquarium out there.
What is the best way to start this culture? I do not have access to a starter culture. Should I try tank water and an algae wafer/fish food? Take a field trip to a local pond or lake for a sample? Tank water and the fert I have on hand? Could you do it with Easy Green or other liquid aquarium fert? I would think so, since there wouldn't be any plants in the water to compete for nutrients. Aeration? No aeration? Artificial light? (I would think the sun is better.) What has worked for you guys?
I'm not in a particular rush but am expecting some fry in a few weeks (I hope!) and it is always nice to have on hand. Plus I'm kind of on a live cultures/fish food kick lately. (I'm eyeing daphnia next, but one step at a time!) Thanks all!

[Daniel]

For me what almost always works is, strong direct all day sunlight plus rainwater plus dead plants.

I have had nice green water cultures form in stray 5 gallon buckets with rainwater and no plant material, but it took weeks for that one.

The culture depends on whatever algae spores waft in on the wind so you never know for sure what you are going to get.

Easy Green would be perfect to get things started as it would take the place of dead plants. I have never used aeration so I don't know if that makes things better.

The most green water I ever made was setting up my 500 gallon tank back in 2007. I juiced it up real good with way to much Amano stuff in the substrate and strong lighting. This is what water my aquarium looked like for 10 weeks straight:

And then, like a miracle it cleared never to be cloudy again.

 

 

[Daniel]

So I just went outside and took a photo. I have about 15 five gallon buckets that serve as my mosquito larva farm. I start those with putrid, fetid, nasty rotting plant material because mosquitos love that smell and will lay vast amounts of eggs rafts in the stinky brown water.

But sometimes an empty, but dirty bucket will end up out there with the mosquito larva buckets. That is what this green one is. It has duckweed in it because duckweed gets stuck to my harvesting net and gets spread around willy nilly.

One of the other green water buckets out there is clearing up because apparently I had Daphnia stuck to the net, and now that bucket has a booming Daphnia population.

[gcalberto]

Honestly all my green water traces back from a single old infusoria culture, which eventually turned green. Ever since I always have a little green water, which jump-starts the culture 

[Terry Ellacott]

I would try tap water with fertilizer left out in the sun , by using aquarium water and lettice you could be introducing the type of micro organisms which will eat the green water algae as it forms.I have two small ponds,one with goldfish which provide the fertilizer and eat the bigger organisms which would feed on the algae ,this pond is constantly dark green .My other pond has no fish and has crystal clear water and is full of the things which eat the algae -mosquito larva ,daphnia ,pond slaters and a host of smaller bugs .