I use the Tunze systemm well worth the $250 I spent... It has never failed me.

Nice thing about it is that it has all the alarms for too much water, or too little in your tank.

Sorry, can't get a picture due to how my sump is positioned in the stand but I bought some ATOs from autotopoff.com. Far cheaper then the Tunze and they are all wired and ready to go. Just add a pump and position the float switches on the mount. I use an aqualifter connected to a 4 gallon bottle of RO/DI. They have one or two float switch systems. The two switch is good as the second one is used as a cut off if the water level gets to high.

Guys.....post photos of your ATO.

I belong to the KISS camp with mechanical float valve ('Wait' brand furnace humidifier valve). No electricals to worry about other than a small air pump on a timer. Gravity feed not feasible at this time since I'm running sumpless and the glass wine carboy (approx 7 gal capacity) is sitting beside the tank. Too bulky to try and raise that up. Next build will be basement sump, so it will definitely be gravity feed. Currently I pressurize the carboy using a small Stellar W60 air pump on a timer. Runs for one minute intervals throughout the day and night (about every two hours). Ok, pictures requested so here they are. Float valve and carboy. I'm sure everyone knows what an air pump looks like. There's one long and one short rigid air tube inserted through the rubber stopper on the carboy. Flex air tubes attached to rigids for air supply and water transport. Short tube comes from air pump, long tube transports the water under pressure to the mechanical float valve in the display. I fashioned the bracket for the float valve out of scrap acrylic and use nylon screws to clamp the assembly to the tank.

http://hlj1yw.blu.livefilestore.com/...XO2/Carboy.JPG

http://hlj1yw.blu.livefilestore.com/...FloatValve.JPG

cool guys keep them coming
did not know about autotopoff.com
where do you all find the small bulk head for the water line to attach to my bucket

I just used a John Guest adapter from Andrew Sherrit however Ocean Aquatics does sell proper bulkheads http://oceanaquatics.com/store/produ...Union--1-4%22/

Ato
 

I use this top off system.

http://www.mops.ca/cgi-bin/SoftCart....html?E+scstore

and this pump......

http://www.mops.ca/cgi-bin/SoftCart....g+-p+DOOS-1137

My Ro unit fills a large , new, 120l garbage can. Which i control.

I have a small powerhead in the garbage can, just to keep the water moving. This system has not failed me yet, and has been running for a couple of years. It also is a source for my water change, water supply. For some reason I don't trust float valves, but that's just me.