It appears you don't have the weight of the tank supported on wood, but screws only, which is no good. It should be over the wood. You want the tank edges resting over wood that goes to the bottom. A 2x4 on each end and in the center would do the trick. I think it's more standard now to have it over wood not screws.
The interior vertical supports are a double stack of 2x4's. This does give him the "T" support you are mentioning, but I agree that a post on each corner and two in the middle would better support the load.
Is the first picture what the front of the tank will look like with the decorative diamonds and triangles? Or is this just the internal structure that will be completely sheeted out?
thank you for reply guys. the four legs supports are double 2x4, one of it is stack again the wood. The first picture is how the outter layer going to be look like. It is a traingle and diamonds shape in the middle so I can't have the support on the corner, however the two in the middle is 2 foots apart so I think it should be fine. Again this is for 55gal.
I would use square head drive or pozi-drive screws. They strip out a lot less than phillips head screws. And stay away from dacro screws. They break. Look for Guard Dog screws. They're more expensive but well worth it.
But the tank will end up weighing over 600lbs once full. I agree with the comment about using the square driver or star driver screws instead of phillips. You may even want to use some L brackets in the corners, or at least triangle block all of the corners to prevent left-to-right shifting.