When I set up my grow, I diligently spent hours covering every inch of three different plastic buckets with foil-tape to prevent any light penetration. The results are really good and the buckets have worked great so far. At the same time, I also set up a couple of fish aquariums as DWC systems to grow tomatoes. Really I did this just for the fun of it, not having any great need for tomatoes that I need more than is grown outside in my garden or can be purchased from the grocery store. The aquariums I set up were a 10-gallon glass tank, and then a smaller 1 1/2 gallon plastic fish tank I purchased at a garage sale and then modified. The larger tank hasn't had any algae growth at all, just massive root growth. The smaller tank had a little bit of green slime growth, but I let the water level go down until I was able to wipe it off with a cloth. Now, about a month later, it seems to be coming back, but it doesn't seem to be harming the tomato plant at all. The roots are still clean, white, and feathery and don't seem affected by the algae at all. So how big a concern is algae really? In a typical DWC grow, which is highly unlikely to last more than three months, could it really threaten MJ?
The biggest problems with algae growth exist in the beginning stages for a plant with new roots. They can be damaged by very little algae. I've never seen thick, dark algae damage roots in rockwool. However, Algae is a breeding ground for other molds and fungi that are potentially damaging (and potentially deadly to Humans, if ingested properly). You can buy a $40 part that's basically an in-line UV light on the water line. It supposedly kills all that stuff, and I've seen them work on a large scale so they must work in smaller setups.
Okay, so it seems as though the actual threat from algae is pretty small, and you would have to be pretty negligent to suffer from it. Maybe if you don't clean your buckets out between grows it could be a problem?
in all reality if you moderate the algae growth, it could be benafical because one algae byproduct is oxygen. which roots need... especialy in dwc.... dont quote me on it now tho.... im blazed out of my mind....
