Automatic waterchange with top off design - please gimme some feedback

[Milad]

So i woke up in the middle of the night (4:37am) with this brilliant design for a automatic water change system

Here is the model of it:


So here is basically what happens
All this is wired into the Apex controller and break out box
A pump sits in the left side of the sump by the skimmer and just waits for XXX time. When the time comes (lets say Sunday 4pm) Apex controller turns off the skimmer and return pump and solenoids. This levels the water out in the sump. The pump on the far right of the sump starts pumping out water from the skimmer area down a drain. Once it hits the lower float valve it stops the pump. Next the pump in the SW mix container turns on and starts pumping water into where the drain pump was pumping out of until it hits the upper float valve. BOOM, water change

After this is done, return pump is on, skimmer is on
solenoids turn back on and the sw mix solenoid starts pumping water into the sw mix container until it hits the float switch. i come home from drinking around 8pm, pour in XXX amount of salt into the sw mix container and wait until the next water change.

thoughts?

The water changes will only be as big as whatever my skimmer area can hold.