pressure treated 4x4s?

I'm not sure about the engineering on this one. You might want to have supports in the middle of the stand, or it might break on you. It's nearly 1000 pounds over a 6 foot span.

 

That stand wont hold brah. If you want to use 2x4's for a tank that big you need to double up the corner post and I would STRONGLY suggest using a galvanized corner brace. (the kind used for decks). Ill post a pic of the type of brace im talking about. You can get these at lowes or home depot. Yes, Im only using 2x4's, but I build this stand for a 30G. Anything larger and i would use 4x4's or doubled up 2x4's with braces.

 

i agree. better beef that stand up a bit

 

stand isn't done yet. Deciding on how I should insert my sump from the rear or the front so I can place my vertical beams. There will definitely be more strength in the corners. All the 4x4s I've seen are all pressure treated, so i won't be going that route.

 

one thing i would make sure of now while your building is to make it so you can take your sump out while the tank is up.
i didnt do this before and ive had times where i wish i could take the whole thing out.
it makes it alot easier down the road for upgrades ect....

 

I would buy some prefab doors. Cabinet shops outsource them a lot of the time as well.