DI Tank size?

My use for DI water in the field has dropped and I am thinking about going with a smaller size tank. Right now I am using a tank with 1.4 cubic feet of resign. I am thinking about going down to either a .45 or .25 in the field and then have a 3.6 for in my shop. my question is if any of you use these smaller tanks and how offten are you replacing them. Right now, three 1.4 cf tanks last me about 6 months to a year. how much can you get out of a .45 or .25? I’m not really sure what amout of water can be put through them? Any help/comments is appriciated.

Scott it looks as if you are getting 2 months out of a 1.4 cub. that should give you .46 of a month out of a .5 cub. so about a half a cub. a month.