in wall tank questions

Hi Andy to answer some of your questions, I would definitely consider an access panel above the tank!!! for feeding and rearranging things, its a must in my book! As for the floor joists go if the tank runs across them you would be ok, It sounds like you have a block wall bellow to help out so I think that should be fine! If you have any doubt then just add a pole brace to support the floor, they aren't very expensive!
As for the lights I think you will be ok, most light housings are not that wide! Just take some measurements and go from there. If you cut the top higher for the access panel it should help with any water splashing. 
Hope this helps.

 

A front access panel is not necessary but you may find it very convenient.  Remember, it's a long way down and I've fell off the bucket more than once while reaching into my tank.  It's very hard to see what you are working on from behind but I like the look of no panel in the front.
My tank sits on a seperate stand that is tied into the wall.  The stand sits on concrete and I have had no issues with settling, there is still a zero tolerance between the glass and the woodowork.
I turned the 2X4's on their side around the edges of the tank so it's only recessed two inches that way but all of the drywall is secure. 
The wall is full depth below and above the tank which means there is a two inch overhang above the tank.  I run a t5 setup and it rests right against the front wall and there are no dark spots or anything that you can notice. 
The whole room behind the tank is lined in plastic so I have had no condensation or leak issues in two years.
If you're intersted, I could post some pictures for you or you could take a look at mine to learn from my mistakes.  Good luck, I think building it was half the fun!
Here's a very early pic

 

Hey Andy,

I put my tanks in the wall line Ballard did. I like it that way.

You can put a window up on top to access it & then use magnets or something to put a panel over it. It is much easier to feed & clean.

The other option which is what I did if you have room is I made my stand so that there is about 18 inches left on 3 sides of the tank. Then I can stand on it & walk around the tank. This works really well for me. I have 900 gallons in my fish room & not too many condensation problems yet. It will help tons if you can leave a window cracked. If not leave an exhaust fan in one of your bathrooms running for a few hours each day.

I would think your floor would be ok, but if in doubt at all they sell support jacks at menards cheap that you can add below in about 15 minutes.

GL
Craig

 

I took 2x8x12's and sandwhiched the original wood..granted i only needed to go 6' on my 220 but it balanced the load. I didn't want to the floor jacks in my basement since the sump was being put under the main tank. This is other option for the floor if space is an issue.