What are you guys doing and how are you making it? You should be making DI first, then running through the R/O membrane. Di water is from a resin based filter that is after your 1 micron sediment filter and before your R/O membrane.
Di water is a little better than what you get with a good softwater system. The R/O membrane is the one that will burn on you if you don't clean up the water first with all those other towers. (BTW, this is part of what I do for a living). You should get a long time out of an R/O membrane - as in years, not gallons, even with the high TDS of the aquifer water. You may need to add a reverse flush kit to your system to keep it clean, if you don't already use one.