Securing legs to base / top of stand ????

[x2uranium]

Best way to secure this????

http://fragtank.freehostia.com/stand1.html

[Esquare]

Don't know about it being the best way but a simple way would be to put another 2x4 on the inside of the stand at the corners in the spot I shaded black
http://reefcentral.com/gallery/data/500/179058Stand_Brace__Small_.JPG

[chemi19]

You can also try a Kreg Jig and pocket screw it

[sailoracu2]

HD has steel workbench brackets that might help. Imo, I would stand the top and bottom 2 x 4’s up, to make it stronger. When they lay flat they will sage under weight.

[DodgeDude99]

you could use something like these....
http://hardware.hardwarestore.com/28-445-mending-plates/tie-plate-102262.aspx

or
the type the use for building trusses, they are typically 3"x5" and have a bunch of spikes that you pound into the wood.

[NanoReefWanabe]

you dont even need a pocket bit set...just drill some holes on angles up and screw it together...the strength of the joint will come from however you skin it...

how big a tank is this for?

[therealfatman]

If you intend to cover the frame with a skin of plywood, it will hold everything together. Use resorcinol or some other waterproof glue as the major structural fastener. Just use nails and screws to hold things tightly and in alignment until the glue can dry. Good glues almost always provide more joint strength than mechanical fasteners and glues work in odd places that are difficult to fasten with mechanical fasteners.

If you intend to cover the frame with a skin of plywood,]it will hold everything together. Use resorcinol or some other water proof glue as the major structural fastener. Just use nails and screws to hold things tightly and in alignment and until the glue can dry. Good glues almost always provide more joint strength than mechanical fasteners and glues work in odd places that are difficult to fasten with mechanical fasteners.

If you intend to cover the frame with a skin of plywood,]it will hold everything together. Use resorcinol or some other water proof glue as the major structural fastener. Just use nails and screws to hold things tightly and in alignment and until the glue can dry. Good glues almost always provide more joint strength than mechanical fasteners and glues work in odd places that are difficult to fasten with mechanical fasteners.

http://www.jamestowndistributors.com/userportal/show_product.do?pid=2060&engine=adwords!6456&keyword=resorcinol_glue

[x2uranium]

Great thanks. Its only for a 75 gallon and I do intend on skinning it with plywood