If it is a cloudy eye, it could be from an injury. If both eyes are cloudy, I would suspect a bacterial infection. Freshwater dips are not very effective if it's bacterial in nature. Freshwater dips are typically good for external/gill flukes or temporary relief from marine velvet (trust me, I know that one on a personal level).
For bacterial infections, I typically use Furan 2 as it is a wide spectrum antibiotic. It will treat both gram positive and gram negative bacterial infections.
Going to the root of the problem, fish will typically get bacterial infections due to substandard water quality. While I know nothing of your system, I would suspect that increased water changes may help. Also, nutrition is also important and you may want to review what you are feeding your fish and make sure it is adequate, nutrionally.