I also had one of those once and the same problem. And I used to use the metal ones for a long time but after a w hile, those sometimes leak at the bottom too when the seal goes bad.
Now, I use the large black rubber 3 gallon tub for my large flock on a heated base in winter and nothing but plastic gallon waterers for the rest of the flock on homemade heated bases in winter. During summer they get a combination of black rubber tubs outside and gallon waterers inside.
Now, I use the large black rubber 3 gallon tub for my large flock on a heated base in winter and nothing but plastic gallon waterers for the rest of the flock on homemade heated bases in winter. During summer they get a combination of black rubber tubs outside and gallon waterers inside.