Rockwool turning brown???

Using GH FloraGro nutes and brand new custom drip system. After 2 days under the drip, the rockwool cubes are turning brownish all around the dripper stake...

Is this normal???

Hoping to G that im not already getting algea or root rot, but the roots are all pretty and white so far..

Are the tops of the cubes exposed to light? Exposed moist surface mixed with hot humid lighting will promote algae growth. I cover mine with a thin rubber sheet that is black on one side and white on the other keeps the light out of the rez also.
High rez temps can also lead to root rot and algae growth. Under 78 degrees is preferable, instead of buying chillers I've seen a lot of people use frozen water bottles that they swap out on a daily basis.

Inconvience vs. cost the life long battle.....

These are very good points, also that frozen water bottle idea sounds primo.
BUT: Isn't algae normally green, or is that like a stupid question?
ALSO: If cube is covered in plastic, wont the nutes from the dripper just run off?

Oh, one more thing, will using an airstone or the like help reduce growth of microbes in me rez?

Isn't there someone in here who can help!?

My rockwool is brown when I get it...perhaps the salts in the nutes are concentrating there and forming MgO, which is brownish in color. Or maybe it's leaching to it's natural color.

algae comes in all forms and colors, do a search for white stuff in my rez, talk about nasty. As far as the block cover and the drip emitter, I would think you could put the emitter under the block cover with alittle ingenuity.
The more dissolved oxygen you can come up with in each container the better.
Anytime you are working with RW just remember that you want the cube to be damp to the touch but not saturated with water. If the cube becomes ot full you can 'flick' it with snap of the wrist to remove excess water as squeezing the product ruins it's drainage capabliities.

Peacefarmer- I know what you mean about color it is like a greenish brown color. My blocks usually have some salt residue on them as the water is full of minerals here even when you treat it with R.O.

get manky crap on your rockwool cubes?

Block the light getting to it, cover it with something white that will reflect the light back up to the foliage, paper will do as least

I block my rockwool cube in tin foil at first then simply used the covers of magazines and cut squares out with slits in them half way up like some sort of cheap-ass cube / stem collars at the bottom. No algea what-so-ever.

My cubes go off green, it's maybe just the way they look whilst wet????

Its normal, i flight is hitting the area where the drippers are then you will grow algae if it stays wet. Brown or green algae will grow. Its not bad just unsightly, its not like it will penetrate into your roots or anything. Do you best to cover it from light and you will reduce it. But otherwise dont worry bout it.

One of the dangers of algae growth on the top of the cube is if it surrounds the stem as this can quickly lead to stem rot and an otherwise healthy plant falls over and dies.