If you can do a couple pwc
's that would be better.
Get a sample to a lfs
for a verification as a cloudy eye could mean aggression/fighting, say if you have 2 male Gourami, injury from wood or decor, or poor water conditions.
I would do 2 50% back to back, pwc
's if you normally do pwc
if you have been lax in pwc
's, the water is probably very different from your tap, and I would do 2 - 25%, to make the water more similar to the tap, and then wait a few hours and do a couple 30% or over night /next morning. Obviously the more fresher water the better. This goes for most fish health in general, and recovering from illness/injury especially.