I realized yesterday that I am having a problem with two of my adult females after I had to dry their tubs 5 times in an hour between the two because it would appear they like to play, lets see how many times we can tip our water bowls over game. It seems like everytime I turn around, atleast one of them has done it.

So my question is there any good way to stop them (or atleast reduce) from tipping their water bowls. The bowls I am currently using are these ones:
http://www.reptilebasics.com/medium-water-bowl
except i get them from walmart. Is there a better/heavier bowl locally available that wont break the bank? I was also thinking that I could make the base larger by gluing a piece of acrylic to the bottom of the bowl, rounding all the edges of the plexi of course. But I tend to overthink things, so I was looking for an opinion.