Designing new sump and water change method

I'm in the process of getting an extra side cabinet for the aquarium, into which I intend to house a plastic jerrican based ATO (freshwater auto-top-off system), put in an automatic daily water change system (also plastic jerrican based) and with that change my sump.

The new sump will be a little larger than my current one (10 cm deeper, 2 cm taller), and should house a refugium where I intend to grow macro-algae to eat up water nutrients and also some live rock on/in which I hope pods will grow to become extra food for the display tank inhabitants.

It should increment the total water volume by 30L, upping it from ~220L to ~250L a 14% increase (58 gals to 66 gals).  Nice considering this is a low water volume system.

Here is a picture of my intended new sump (Portuguese text, sorry for that if you're not Portuguese enabled :-) , refugio means refugium, retorno is the return pump area, skimmer is, well, skimmer.... :-) ):

My daily plastic jerrican automated water change system is going to be like this:

A. One 20L plastic jerrican will hold new, virgin satwater. Inside the jerrican will sit a slow 60 L/h water pump, connected to a hose that takes the water to the sump.
B. Another 20L plastic jerrican will serve as a container for removal of used/old satwater from the sump.  In the sump a slow 60 L/h pump will sit, connected to a hose that ends inside this "B" jerrican.
C. Using timers I'll turn on pump "B" for 2 minutes every day, removing 2L of used water, after which I'll turn on pump "A" for 2 minutes, adding back 2L of new water.

Every 8 to 9 days I just remove jerrican "B", empty it and put it back in the cabinet, remove jerrican "A", refill it with new water and put it back in the cabinet.  I'll do that moving them with a dolly (a homemade "skate") so I don't have to carry weight around, after all, wheels were one of the first inventions of mankind, right?  I'm not in need of "heavy jerrican" workouts.

If I travel I can setup the timers to change water slower (i.e. 1 minute per day), extending the autonomy of the system but still ensuring water is changed.

I was inspired to create something like it by the article linked below, and also because I want an easier way to change water frequently.  Doing a half an hour to 45 minute 20L to 30L water change during the weekends is something I haven't been successful in keeping up with.
Reefkeeping October 2005: Water Changes in Reef Aquaria (http://reefkeeping.com/issues/2005-10/rhf/index.php#13)

My plastic jerrican based ATO (freshwater auto-top-off system) will follow the same reloading principle.  The basic operation is like any other ATO with water sensors and a pump in the freshwater container.  But the freshwater container will be one or two 20L plastic jerricans which I'll refill as needed, moving the jerricans between my RO/DI filters and the cabinet on my dolly.

This plastic jerrican "design" is somewhat inspired by the ink cartridge change in ink jet printers.  Remove the used cartridge, pop in a new one.  The concept is the same.  No carrying buckets, doing siphons in the living room, no accidentally wetting the living room floor, like I've done so many times, etc..

flpaoli / snorkeler