Drawing my thoughts has always helped me in planning. I decided that it would probably work best to have the tanks about 35" up for the easiest access and viewing. I had originally thought about setting them on a vertical stand but access to the top and bottom tanks would be limited. Here is a quick drawing of the system layout.

All 3 tanks will be plumbed to a common sump.

The plumbing will be pretty basic considering the tanks are drilled. 1" bulkheads for the drains and a .5" for the returns. I will probably use PVC for the returns and then just vinyl tubing for the drains. This will be set up in my basement so it does not have to look pretty (wife said "go for it").

Ball valves will be on the return lines to control flow. I will probably add a powerhead or two to each tank for additional flow.

The sump will likely have to be a DIY project and will include a drain/skimmer section, a refugium in the middle and then a pump chamber with the auto top off. I have a mag 9 that I can use for the return pump.

The tanks will be bare bottom but I will install a deep sand bed in the refugium for denitrification. I will also keep some chaetomorpha macroalgae for additional nutrient export. I have a small light that I will use for the refugium to keep the macro growing. I will run this light on a reverse timer from the main lights to help control day/night pH changes.

Next I am going to drop by the big orange box hardware store today and see if they have some racks that will work as stands for these tanks?