Semi automatic Water Change Idea

[Milad]

Hey guys, im looking to do the following
Add more room for my liverock (running out of space)
and setup a almost automatic water change
Below is the diagram i have for an idea

There is two containers, one on the left is just water, one on the right is water and liverock

What i will be doing is pumping with ehiem 1260 from the sump into the left container, it runs down to the bottom and goes into the right container which has a herbie setup back into the sump

when i want to do a water change i turn off the middle ball valve (in-between the containers) and open the ball fall that drains outside

Thoughts? bad? good? its pretty simple. This will give me more room to put liverock and a 10% water change every week in under 30seconds (mind you i have to refill the left container and add salt)