A single treatment of Clout is supposed to run for 72 hours. I wouldn't change if it seems to be helping. If it is helping, wait a few days to see if they continue to recover. If they are still doing better, you may have it licked. If they seem to be slipping back I would go with a second dose.
The cory may have a bacterial issue going on from the marbles & leftover food. Corys will usually take care of any leftovers on the bottom, if they can get to it. Being bottom dwellers puts them up close to the bacteria from the leftover food.
Just by cleaning the bottom, and doing water changes you may help the cory. If not an antibiotic such as Maracyn & Maricyn II may be needed.
The cory may have a bacterial issue going on from the marbles & leftover food. Corys will usually take care of any leftovers on the bottom, if they can get to it. Being bottom dwellers puts them up close to the bacteria from the leftover food.
Just by cleaning the bottom, and doing water changes you may help the cory. If not an antibiotic such as Maracyn & Maricyn II may be needed.