Exactly what the title says. I’ve done some research as to why but the thing is is that it was doing great and flourishing to where I was harvesting 1-3 quart bags of chaeto every other week. My last harvest I took a little too much out to where there was maybe a golf ball size (when compressed) and that’s when it started dying. I have a cheap grow light off Amazon. Im dosing iron. Nitrates at 10ppm and phosphates rose up to 0.1ppm after adding new livestock and harvesting chaeto. My fuge is low flow but has never been an issue in the past. Could it be that now that is so thinned out my light is frying it? The light is literally 1” from the surface (to minimize light getting to the rest of the sump), but once again it’s always been like this. I have a 29gal reef tank with 20gal sump. I do turn the chaeto every couple nights or when I can remember and I think lights are on 12 or 14 hrs. Maybe try 6hrs on 6hrs off? Im Just at a loss and will take any insight or advice