not too sure but peroxide is not suppsed to be used all the time, it kills all the benificals and fungies living in the buckets. also only pure food grade peroxid is to be used and its cheeper. 10 bucks for a liter of 35% peroxiode . found at any hydro store..

also just an obeservation but I have seen this happen with toxic off gassing too. such as with plants next to swmming pools full of chlorine, or also in new rooms with toxic chemicasl still in the air such as adhesives or paint thinners.