got the plexi cut for me at home depot. i siliconed it around on both sides. it also came out a little longer than the exact width of the tank so its kinda wedged curved in there and stable even before i siliconed which worked out nice.
given the amount of time she now spends in the water im surprised more people dont recommend water sections. she gets a lot of exercise by swimming around and shes pretty good at swimming fast. its also easy to feed in the water because i dont have to worry about her ingesting any substrate.