Yes I did went to notch the corners out. I have a VERY nice band saw that is made for this type of work. It will cut 10" thick wood and of course using one piece is much stronger than glueing/screwing them together and easier if you have the right tools. I from the start had disigned the stand this way - notch and not put lots of 2x6's and 2x4's together for the legs. I know lots of people do it that way and it holds up but I have the proper tools to give a very nice surface - that's way you buy these cool tools
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On the inside it will give it another area to attach to the 2x6 which again will give it more strength. Thanks for the suggestion and I did see a few others with larger tanks (240+) doing it that way - but by far more seem to use either 4x4's or 4x6's for the legs.