Ato all the way.....try autotopoff.com and invest in the double float switch. The extra layer of insurance is well worth it. I go through over 2 gallons of water a day in my 210. There are other factors that also contribute to evaporation. Are you using evaporation to cool your tank...aka.fans and is your tank covered or open.
I have a 125 was getting a lot of water evaporation so I got Custom King to build me a auto top off unit with my RODI unit directly hooked up to it good luck