Yes Paul, thats what I was thinking. But level with the bottom of the tank. So the shelf covers the foam and a little bit of the sand.

this better?

Me Likes, Paul :D

What program you using to draw with? I have Autocad 2008, but I'm not that good with the 3D aspect.

I draw freehand on paper:)

I use Iron Cad, it's a solid modeling package that I have used for years, it allows me to go from a solid to CNC easily, very user friendly.

do you use 3D for your CNC? Thats the reason I got Autocad myself. Was for my Mill. But I just use it for X-Y drawings and have a CAM program that I enter the Z's into. It's only a 3 axis mill, and I havn't goten into full scale 3D with it.

We run a number of methods, Solidworks included, then into cad cam to verify, I have 16 CNC's and all are slightly different so they have to be dealt with differently in the way you post to them.

16, damn Must be a nice shop :D

Oceans Motions must not be the only thing you produce.

I figured I'd just jump in
 

I am building/planning almost the same thing except I have the ledge already there. So, I had an idea that I figured I'd pass on.

A while ago I got to talking to a fellow that does custom granite kitchen counters as I am thinking about re-doing my whole kitchen, and I asked about a custom granite piece being made up for the ledge in front of my tank (some strange angles and 8 1/2 feet long X 8" wide) and as it turns out -- Most granite sheets com in about 6-7 feet wide, and they custom cut the counters and very regularly get 8" to 12" pieces cut off that is normally wasted as there just isn't that much demand for 8" counter tops.

End result -- I got a price of about $100 for a piece of granite that will butt right up to the tank and act the same as the tile shelf you are thinking about.

You might want to consider it -- as after all the edging material/tools/grout you would be more cost than custom stone work.
PS. I really really hate ceramic tile -- a lot :)

Where did you get this piece of Granite?