White Tahoe Cookies

Three weeks in the White Tahoe Cookies are progressing as expected. One had some slight yellowing on the edges of a few leaves, I've kept my eye on it but haven't seen as progression. I think this may just be related to how the seedling first emerged from the seed pod. I've been feeding them a low dose of Cocos and Roots Excelurator and they seem happy enough. Both pots have some algae forming on the surface of the coco, but I'm not too concerned about this. I've noticed that this occurs early on in the grow while using high frequency fertigation, but it will go away once the canopy blocks more light to the surface of the coco. I suppose I could get a HydroLock setup, but I haven't had any issues with just a bit of algae on the coco. Monday morning I checked on the plants, They now have 4 nodes and appear quite healthy. I topped both of them, just removing the new growth tips. Wednesday morning I noticed a couple small orangeish/brown spots on one of the fan leaves. I've had a bit of mildew on some non-cannabis seedlings in my grow room and because of this I decided to treat the room and plants with H2O2. I diluted 1 ml of 29% hydrogen peroxide with 4 L of tap water, let sit for half an hour and then applied it to the foliage, the top of the coco and the walls of the tent.