I find those gallon waterers are less likely to turn over if they are half full or more. Since you are using Corid, and may not want to keep it full, you could place some rocks in the well to weight it down. They may be jumping into the food and over onto the waterer and flipping it. I usually place the water and food about should height of the shortest chicks. A 1 or 2 inch flat board works well, and wish tall enough 2 bricks underneath it work well. Baby chicks love to climb on the water and food, don’t they?
Show them how to use a rabbit/hamster water bottle. You'll never have that issue again!
Is that easy for them to learn?