You will never get rid of them in your current tank, with the frogs in there. You could move the frogs to the new tank, then treat every plant (not just broms) in the old tank with a systemic, and that might knock them out. But systemics linger for a long time, so you would need to leave those plants in place for months and potentially change out all the soil before introducing any herp into the old tank. Bleach treating, soapy water, etc. will not eliminate them from your broms.