It would appear that you are overwatering. That won't be the only problem you're encountering but it'll be the first and foremost thing that you'll need to address. The one in the clay pot is worse than the other and it's more than likely because there appears to be little or no perlite in it whatsoever.

Repot the smaller one.. and spread your waterings out more.. you should never be watering a plant more than 3 or 4 times a week... NEVER. No matter what size it is or how old it is.

Cheers,
Bob.