[mistergreen]

What algae do you want? I assume brown , green spot. They don’t need a lot of light or nutrient, maybe just a drop of ammonia. You can get ammonium chloride off amazon.
or dirty tank water will work fine.

 

[mistergreen]

In the shade or by the window should work. No circulation. You’ll need to feed ottos algae wafers too for a balanced diet.