Advice? 400g In-wall idea. Advice on stand?

Is this going on a concrete floor?

Stand looks legitimate. I would fix the two ibeams together so you could put 1" bolts between beams and CMU as a leveling system. You would need a plate with a 1 1/8" hole atop the CMU to allow the bolt to slide up and down.
I despise fixed stands. Takes a large time investment to shim just perfect. with levelers you can put 1/4 inch water in tank, spin some nuts and get it just right with small turns

 

Whats the depth. Need to really focus on the weight per square inch (weight within footprint). If its a 6 ft 400 Gallon this has to be deep and tall. On rough numbers a 2x4, 2x6 construction can likely support this. Could also go beefer and do cradle bracing or 4x6, 4x4 studding.

 

Having a 30" deep acrylic tank I would never, ever go acrylic again. I cant even imagine the string of obsenities an acrylic tank that deep would prompt me to say come cleaning time! Sounds like a great project though!

 

4 - 1/2" bolts hold the receiver to the frame, a 3/4" pin secures the hitch to the receiver and a 1 1/4" bolt on the ball secures that to the hitch.. It's the grade that you use. You want grade 8. They are the strongest and will resist rust better. cost difference per ibs is small over grade 5 or 2(standard/not specified). But yea. Cinder blocks are cheap, mortar is decently priced and a couple I beams from the place on 6th St SW cedar Rapids should be reasonable.

 

Are you planning on having any kind of access panels above the tank on the display side? At 36" wide and 36" deep I'm afraid you wouldn't even be able to reach the bottom of the front panel if you only have access from the back. That's a long reach out and down.
My 300 is 30" deep and 24" wide, its a huge pain in the butt to reach across and down, couldn't even imagine what it'd be like at the dimensions you're thinking. One thing I've learned through my years of keeping tanks, accessibility goes hand in hand with maintenance. The harder it is to access things the less likely you are to regularly maintain them because of the struggle it requires.

 

My cut off if I upgrade is armpit to tip of thumb.

 

Remember you don't want your armpit in the tank. So figure the scraper +4", less the pit -4". Deodorant does not wash off well and probably not something you want leaching in the tank. And you will likely be going to tank bottom far more often than just cleaning

 

You also lose leverage the deeper you go and risk busting corals as they grow.....and you might end up with a tank that looks like this after a couple of years.

Note the bottom few inches of coraline. Did I mention I am not a fan of deep acrylic tanks?

 

@Dave picture?

 

Sorry. Struggling with uploading from my phone. Will do tonight.

 

Here is the pic I was referring to. The problem is not only the leverage but the limited choice of tools to use (basically plastic on plastic) and the darn stuff still scratches if you look at it wrong!



And I'm 6' so no t-rex arms here . Currently in the process of planning a reboot with this system and going to glass (probably a 300DD which I looks like made your short list as well. Good luck with whatever you choose to do as it will be a great project!

 

If you do go with an acrylic tank I recommend getting a mighty magnet. I have had one for every acrylic tank I've ever owned and wouldn't have one without one. My tank is by no means perfect but far better than it would be with out it. I've had one for up to 1 1/2" acrylic before and I know they make thicker. Different pads for different tasks, all replaceable to ensure a clean pass and less scratches.