Re: What are some things I can add to water to promote algae growth?

Spirogyra, like Chlamydomonas and some other green algae, are fresh water organisms and frequently form what is commonly called "pond scum" on the surface of fairly stagnant pools of water.

Some basics necessities for growing these algae are light (for photosynthesis) and a nitrogen source. You can use artificial lights (flourescents) or a window sill, but you do not want the light intensity to be to great (avoid a direct light source, like a west facing window). You could get nitrogen by adding some diluted plant food like Miracle Grow, etc.

You should avoid tap water (because of the presence of chlorine) and use some distilled water (from the grocery store would be OK). Check the pH of the water if possible; it should be between around 7. If higher (more than 7.5-8) or lower (less than 6.5) you will need to reduce or increase the pH of the water. Also avoid heat; room temperature 70-75 degrees F should be ideal.

In a parallel effort, you could add (sterile) soil to a culture, in an attempt to provide the nitrogen the algae need for growth.