algae growing in the rockwool
 

hi ron,
is algae growing in the rockwool of my growing cup a cause for alarm ?
pathetic grower

Hi pathetic grower (been their)
Algae is a by-product of hydroponics and is caused when light shines on water. It's not harmful but you can cut down on it growing by blocking the light from reaching the water with a paper plate, with a hole and a slit to wrap around the stem of your plant. The white paper plate also reflects light back up to your plants.
Ron