Hey you can add 2 tsp per gallon of 3% hydrogen peroxide. It will kill off the bacteria that is blooming feeding on the decaying roots. The peroxide breaks down into water and a rogue O molecule. If that molecule runs into bacteria it kills it. If is hits another O molecule it adds oxygen to the water. It is a win win. Since it breaks down you will want to add another 2tsp about every 4 days or if the water gets cloudy. After a couple weeks the dead roots should be broken down. Just monitor your water for cloudiness after that and start the h2o2 again if you see cloudiness or an unusual ph fluctuation. You can use 3 tsp max but 2 has always fixed my issues. Hope this helps.
