I purchased some amazon frogbit recently. As I have done with other new aquatic plant purchases, I soaked the frogbit in a dark pink potassium permanganate solution for 30 minutes and then in alum solution of 2 tablespoons per gallon overnight to help control any snails. This has not harmed other plants I have, like crypts, java fern, water sprite, et al. However, the amazon frogbit began deteriorating after a few days of floating in the tank, with the leaves turning yellow and then brown. It appears to be rotting. Can it not withstand dips? Or do you have any other thoughts about why it has deteriorated. I have two out of six that are hanging on. Thanks.