shit, i'm having the exact same issue...it seems to make my plants seem as though they are Mg. defficient when really it is a algea problem...Yours is an algea problem and it does have to do with light and water temps...my water temps can get up to 80 if I don't monitor them and that is just asking for this shit to grow all over the place...I guess that is the first step in fixing the problem, but now I'm right in the middle of a grow, so I'm gonna try to finish them out...Looks like the plants should finish fine, they will just finish super early as a natural reaction, kinda like they are dieing...it should only affect weight with the end product...if you checkout my thread, you can see that the plants can survive fine with this stuff, but it really makes leaves die off super quickly when it gets a hold of the roots...I'm gonna flush with Hydrogen Peroxide as I've never tried this before and see what happens.
-sD