Recently a couple of my bogs had areas of excessive moss so I treated the areas with Iron Sulphate. I saw dramatic results within a couple days, so I decided to try the Iron Sulphate on a few disposable orchids in my GH. Results were equally dramatic and after a couple weeks I've noticed no damage to the orchids while the treated moss has, in most cases, turned black. I dissolved 1 teaspoon of FeSO4 in one gallon of 35 ppm water and just sprayed the orchid and moss with a bottle sprayer. TDS of the solution was 780 ppm.