Thats a nice looking frame you have there. Did you and your husband design it yourselves or did you use the design from somewhere else? The design looks like a combination of different ideas I have seen on the Internet.
While that joint won't be under a tremendous amount of load from the tank, your method of joining the wood makes a lot of sense. The joint comprised of butting 2 x 4s could have a tendancy of pulling apart due to the tendancy of a 2 x 4 wanting to twist. Your joint should remain sound and stay together without any problem.
What kind of 2 x 4s did you use? They look a lot like Douglas Fir.
Pre cutting all of your pieces is also a great idea. It allows you to check to make sure that your measurements between the pieces are precise which will help to make a square and level stand.
I would like to see some full stand shots as well.
Thank you guys for your comments.
It is just plain dougfir.
The design is defenetly some mixed combination of every sort of things
I was looking for plans on the internet and could not find the exact thing I wanted for, so we just started without a fix plan.
As I said we calculated the height of the stand during cutting the wood
Thanks fot the comment guys