Advice? Tank Build! What is your ATO container?

I have a 20g aquarium (buck/gal sale!) that I use for double duty. It's normally my ato tank but when its time to do a water change I top it off w rodi, throw in the salt, turn on the mixing powerhead and heater and do my water change. As soon as w c is done I fill it back up with rodi and it's my ato tank again. This saves me space of having a mixing tank and a ato tank. I've also found that the little bit of stuff that precipitates out of the salt mix (I use Reef C's), some of that seems to dissolve back into the rodi used for top off.
This is on a 90g with a custom 20g sump and 20g fuge.

 

When I put my sump together I installed an overflow 1/2" below the top of the sump and ran it to a drain. This gives me a little piece of mind for worst case scenario and also gives me a great place to siphon a gravel vacuum to when doing tank cleaning.

 

Buck-a-Gallon sale is on at Petco!!!

 

Thanks everybody for all the input! I ended up reworking my plumbing a bit and moved the 40 sump all the way over. This gave me just enough room for a 10 gal tank. We will see how long between fill ups this gives me once I've got it up an running. It's always fun to hear and see what everybody else is using!

 

I thought of doing something like what you are talking about and I still may. I wish I knew how to create a hinged lid with acrylic. Oh well more research!!

 

Also as a side note... If anybody is looking for a quiet overflow set up... I have two overflow weirs and I am running a double herbie set up. It is dead silent.

 

you can buy acrylic hinges that glue right on. I got some in Des Moines at Midland Plastics.