Im putting two 6 Inch 1/2" thick sheets of glass in the middle, spread evenly apart to make 3 openings. And I'm also going to put supports on the ends, 3" wide at 1/2" thick Just to keep the edges supported better. Then a leak check... Then I make plexi glass lids, then I start putting rocks and stuff in it! Can't wait to get my 300 gallon set up!