Thanks Mark...
Some simple thought goes along way!!
Here is another simple thought I had for this system.
I wanted to be able to do a water change without turning off ANYTHING.
This has been done before, the idea is not mine, but I figured I could make it work for me. Without using a pump.
Alls I needed was an isolation tank the could be ball valved on line, or off line.
That is the far right ( taller) tank in the pic
The shorter tank will be the fuge tank. It will drain into the main sump at the skimmer.

So the isolation tank drains into the fuge tank.
This top will hold lights for the fuge, and allow me to stand on it to do maint. on the DT
This shows the drain line coming from the overflow on the DT. It dumps into the isolation/WC tank.
There will be a valve in the line to divert the drain water to the fuge.
This line is hooked to the Mixing barrel and with a turn of the ball valve I can replenish the isolation tank with fresh saltwater
The isolation tank drains directly to the dry sink
