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)

http://dl.dropbox.com/u/2361330/Aquarium%20build/Water%20Change/WC%20v1.jpg

[Albertan22]

You might want to add a "T" in your sump drain line into your rock tank and put valves on both downstream ends. That way you could just isolate the water change tank and keep everything else flowing while you're refilling, mixing salt and heating the water in that tank.

Where does the pipe that goes outside go? I don't think large volumes of salt water would be good for your grass...